Contraceptive pills and injections can be hard to obtain in the developing world. Many women must take a day off from work and pay significant travel expenses to get to a clinic. Even women in the U.S. can face logistical challenges in filling prescriptions on a regular basis.

Contraceptive implants for the arm, effective for at least three years, are a popular alternative, but insertion and removal can be challenging. A team of Johns Hopkins University biomedical engineering undergraduates and recent grads has developed a new implant insertion and removal training kit to make it easier for health care workers to learn to administer the implant.

Commercial arm models on which to practice inserting the matchstick-size devices don’t replicate skin and fat well. But the students’ arm model has layers of silicone that mimic how skin, fat and muscle behave when pinched, pressed and punctured. Trainees can peel back the “skin” to see if an implant was inserted correctly, between skin and “fat.” If it’s stuck in the fat, it’s too deep—in real life, it wouldn’t work and would be difficult to remove, explains team leader and recent graduate Taylor Lam.

The model is part of the students’ CITT (Contraceptive Implant Training Tool) Kit, developed during a design class. Johns Hopkins Hospital nurses and residents who administer the implant in Baltimore have tested the model and say it’s more lifelike than any other they’ve used.

Next up is a year of design finalization and field testing by students with assistance from Jhpiego, a nonprofit Johns Hopkins University affiliate that focuses on global health issues. If the silicone holds up in tropical temperatures—as it has in hot oven tests—the kit may be available to train health care workers around the world within three years.