One tube, Infant Size, Blood Pressure Bladder for one-hander B/P units. (meaning that the unit has a bulb and gauge as a single unit as called a one-hander)
If your Blood pressure unit needs two tubes to function see the following selection of two-tube blood pressure bladders
The replacement units slide back through the slot in the cloth cuff. Size: 6 3/4" long x 3 1/2" high (+/-)
These bladders have many more uses than just for checking blood pressures. Many hobbyists and inventors use these unit for different purposes.