The 24W218 Santoprene Diaphragm Kit from Graco that includes:

40390 and 40391

Also called a timing beltFor model #'s 254974

Model LazerVac Series Vacuum

Jet Tools - JTM-2 Mill With X-Axis Powerfeed 11.3 SCFM The 24W218 Santoprene Diaphragm KitDetails Jet 690006 Description Three stage power down feed with auto stop, high precision Class 7 spindle bearings and the rugged stability of Meehanite castings ensures you get everything you need from the JTM 1 and 2 models. The internally cooled spindle head prevents seizing, and JET precision engineering ensures superior results with all the features you've come to expect, all backed by the industry leading JET Two Year Warranty Jet 690006