This is a Rola-Chem Tri-Roller 3-Wheel Squeeze Tube Roller that is used on Pro Series peristaltic chemical pumps. It is not used on older models that use the 2-Wheel H-Block design and not used on model RC252 (see #RC523332).
This Tri-Roller works on the following models: RC24/53, RC103, and RC503.