The figure reveals the vacuum clutch system. This type of clutch uses the present vacuum within the engine manifold to function the clutch. The vacuum clutch consists of a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve.  Opt for a clutch package so you have got matching parts. https://cristianardoz.thezenweb.com/5-essential-elements-for-clutch-plate-71015493