What is the soft sleeve/cylinder that is being used here?

[CloudyMascJock]

Came across this hot vintage pumping video and one of the guys used what seems to be a soft silicone sleeve of some sort that attached to the regular pump and then squeezed his dick as he began the pumping process. Anyone know what it is he’s using?

 

[huge-girth]

No idea.

 

[DLD]

No idea.