1. Omron ElectroTherapy Pain Relief Device: This TENS unit is compact, portable, and easy to use, making it a great option for physical therapists who need a reliable, high-quality device that can be used in a variety of settings. It has several preset programs and modes to choose from, and it comes with a variety of electrode pads.
2. TechCare Plus 24 Rechargeable TENS Unit: This TENS unit is designed for professional use and offers a wide range of modes and intensity levels. It's rechargeable and also has a built-in timer, making it easy to use for physical therapists.
3. Pure Enrichment PurePulse Pro TENS Unit: This TENS unit is designed for both professional and personal use. It's lightweight, portable, and easy to use, and it comes with a variety of preset programs and modes to choose from.
4. iReliev TENS + EMS Unit: This TENS unit is designed for professional use and offers a wide range of modes and intensity levels. It also has a built-in timer, making it easy to use for physical therapists. It also has the capability of delivering electrical muscle stimulation (EMS) which can aid in muscle re-education.
5. HealthmateForever Pro-12AB TENS Unit: This TENS unit is designed for professional use and offers a wide range of modes and intensity levels. It's rechargeable and also has a built-in timer, making it easy to use for physical therapists. It also has multiple channels and pads for treating multiple areas of pain at the same time.

It is important to note that these are just a few examples of TENS units that are popular among physical therapists and may vary based on the individual therapist preferences and professional experience. It is always good practice to check with your therapist for specific recommendations based on your condition.