I would give that a 4. 

This is a very good safety device.  It attached nicely to prefilled syringes.

The only difficulty with this one is that it may take a second hand to activate the safety mechanism. 

The safety mechanism once activated is wonderful. 

Bobbi Jo Hurst, MBA, BSN, RN, COHN-S

Employee Health/Infection Control Nurse

Orthopedic Associates of Lancaster