InTENSity Twin Stim III TENS & EMS Combo Unit – DI3717

The InTENSity Twin Stim III, model DI3717, is a portable, dual-channel device that combines transcutaneous electrical nerve stimulation and electrical muscle stimulation.

TENS programming provides sensory-level electrical stimulation for clinician-directed pain-management applications. EMS—also commonly called NMES—stimulates motor nerves to produce a visible or palpable muscle contraction for prescribed muscle-rehabilitation programs.

Unlike devices built primarily around body-part presets, the Twin Stim III gives the practitioner direct control over frequency, pulse width, intensity, treatment time, and mode-specific settings. Its four TENS programs and three EMS programs allow the device to support both pain-focused stimulation and structured contraction-and-relaxation programs.

The unit can operate from a replaceable 9V battery for portability or from the included AC wall adapter. It comes with two lead wires, four reusable 2" × 2" electrodes, a battery, an AC adapter, an operating manual, and a carrying case.

Treatment mode, settings, electrode placement, and duration should follow the prescription and current operating manual.

• Combination TENS and EMS/NMES stimulator
• Compass Health/Richmar item DI3717
• Prescription Class II medical device
• Two isolated output channels
• Supports one or two electrode-pair arrangements
• Four adjustable TENS programs
• Three programmable EMS modes
• Output adjustable from 0–105 mA per channel at 1,000 ohms
• Pulse frequency adjustable from 1–150 Hz
• Pulse width adjustable from 50–300 microseconds
• TENS Burst rate adjustable from 0.5 to 5 Hz
• EMS contraction time adjustable from 1–60 seconds
• EMS relaxation time adjustable from 0–60 seconds
• EMS ramp adjustable from 1–6 seconds
• Treatment timer adjustable from 1–60 minutes or continuous
• Independent intensity adjustment for each channel
• Automatic control lock after 30 seconds
• Open-circuit electrode detection
• Replaceable 9V battery operation
• Included AC wall adapter
• Removable belt clip
• Compact digital LCD interface
• Four reusable 2" × 2" electrodes included
• Carrying case included
• One-year manufacturer warranty

The ranges above are documented in the current sell sheet and Revision C manual. The manual specifies a ±5% tolerance for settings and ±10% tolerance for output intensity.

The Twin Stim III includes four TENS programs. The current manual gives these clearer names than the generic “Mod 1” and “Mod 2” terminology used in some marketing material.

The Burst program uses a fixed 100 Hz pulse frequency within each burst while allowing the overall burst rate to be adjusted from 0.5–5 Hz. The other programs permit frequency adjustment from 1 to 150 Hz.

Avoid assigning each mode to a specific diagnosis or claiming that one mode is always best for either acute or chronic pain. A safer presentation is the following:

• Normal: steady stimulation
• Burst: rhythmic groups of pulses
• Pulse Width Modulation: automatically varies pulse duration
• Pulse Rate Modulation: automatically varies pulse frequency

Mode, intensity, frequency, pulse width, and treatment time should follow the practitioner’s directions.

Synchronous mode

Both channels stimulate at the same time and follow the same contraction, ramp, and relaxation cycle. This can support prescribed bilateral or paired-muscle applications where both electrode pairs should activate together.

Channel 1 completes its stimulation cycle before Channel 2 begins. The manual requires the programmed OFF time to be at least as long as the complete ON cycle, including contraction and ramp periods.

Channel 2 begins after Channel 1 has already started, based on an adjustable delay. This creates overlapping but offset muscle-stimulation cycles rather than completely simultaneous or alternating output.

Contraction time is adjustable from 1–60 seconds, relaxation from 0–60 seconds, and ramp from 1–6 seconds. The manual defines the complete ON time as contraction plus ramp-up and ramp-down.

Automatic control lock

The front-panel controls lock approximately 30 seconds after the user stops changing the program or intensity. This helps prevent unintended setting or intensity changes.

To unlock the controls, press either channel’s intensity-down button.

When output is at or above 12 mA and the unit detects an open circuit—such as a loose lead, disconnected electrode, or pad that is not making proper contact—the affected amplitude resets to 0 mA.

This feature can help identify the following:

• A disconnected electrode
• A loose 2 mm pin connection
• A lead wire not fully inserted
• A damaged cable
• A pad that has lifted from the skin
• Dry or worn hydrogel

It does not replace visual inspection of the electrodes, wires, skin, and connections.

These steps summarize the operating manual and should not replace the prescription or complete instructions.

1. Review the prescribed settings. Confirm TENS or EMS, program, frequency, pulse width, intensity, treatment time, and any EMS ramp or work/rest parameters.
2. Install the 9V battery or connect the AC adapter. Follow the polarity and power instructions in the manual.
3. Connect the lead wires. Insert each device-side plug fully into the selected channel.
4. Connect the electrodes. Insert each 2 mm pin completely into the electrode socket so no conductive metal remains exposed.
5. Prepare the skin. Apply electrodes only to clean, dry, intact skin. Clip excessive hair when necessary; the manual says not to shave the stimulation site.
6. Place each complete electrode pair. One active channel requires two electrodes.
7. Turn on the device and select TENS or EMS.
8. Program the prescribed parameters before increasing intensity.
9. Raise each channel gradually. TENS is generally used at a strong but comfortable sensory level. EMS is commonly adjusted to obtain the practitioner-directed muscle response.
10. Turn the output down before repositioning or disconnecting anything.
11. After treatment, turn the unit off and return reusable pads to their liners.

Applying pads from the center outward, avoiding stretched adhesive, supporting excess lead-wire length, and removing pads in the direction of hair growth.

The Twin Stim III uses standard pin-style electrode connections. Balego offers several appropriate accessory categories:

• 45-Inch TENS/NMES Replacement Lead Wires
• Balego TENS/NMES/FES Electrodes
• Electrotherapy Electrodes
• TENS Electrode Guides

Before substituting pads, confirm:

Read TENS/NMES Electrode Connectors: Pigtail vs. Tab for additional connector guidance.

Twin Stim III vs. other Balego electrotherapy devices

The Twin Stim IV is a rechargeable two-modality device with 18 TENS and 18 NMES programs, the Select Combo II is a rechargeable four-modality unit, the Balego EMS Digital is a dedicated dual-channel NMES device, and the Twin Stim Plus is a four-channel system with TENS, EMS, IFC, and Russian stimulation.

The Twin Stim III is not automatically inferior because it is an earlier generation. It may be preferable when a practitioner wants direct access to frequency, pulse width, ramp, contraction, relaxation, and delay settings without navigating numerous body-area programs.

The Twin Stim IV may be preferable when rechargeable power, body-part presets, custom U1 programs, and compliance tracking are priorities.

• Both TENS and EMS are required.
• Direct manual programming is preferred.
• A replaceable 9V battery is useful.
• AC wall power is needed for stationary use.
• Synchronous, alternate, and delay EMS patterns fit the prescription.
• A strong adjustable output range is required.
• Body-part presets and IFC or Russian stimulation are unnecessary.

• Rechargeable operation is preferred.
• Preset body-area programs simplify setup.
• Numerous TENS and NMES programs are desired.
• Compliance records are useful.
• The user prefers a guided interface over traditional manual programming.

• IFC and Russian stimulation are needed in addition to TENS and NMES.
• Rechargeable operation is preferred.
• Two channels provide enough electrode coverage.
• Preset and customizable programs are both important.

• More than two independent electrode pairs are needed.
• Large or multiple treatment regions must be covered.
• TENS, EMS, IFC, and Russian modes are all required.
• Two independent treatment timers are useful.

Rx Only. Use the InTENSity Twin Stim III only as directed by a licensed practitioner and according to the current instruction manual. Do not use it with a demand-type cardiac pacemaker or implanted defibrillator. Do not apply stimulation through the head, over the front or sides of the neck, over cancerous lesions, or over swollen, infected, inflamed, irritated, or poorly innervated areas. Pregnancy safety has not been established. Consult the prescribing practitioner regarding epilepsy, heart disease, circulation disorders, impaired sensation, recent surgery, or unexplained pain. Stop treatment if stimulation causes persistent pain, burning, skin irritation, or another unexpected reaction.

• TENS vs. NMES: Differences, Uses and Device Guide
• TENS/NMES Electrode Connector Guide
• TENS Unit Guides and Mode Education
• NMES Protocols, Settings and Electrode Placement
• Contact Balego