These kits give you a full selection of RPM values to choose from. The individual modules and Module Selectors plug into the RPM Activated Switch. The Modules or "pills" come in sets of five within a 1,000 rpm range. For example, the 4,000 rpm set includes 4,000, 4,200, 4,400, 4,600 and 4,800 modules. 

You will need 2 sets of "pills" for the window switch. 1 set to activate the switch and another set to de-activate the switch. For example, 3,000 rpm pill to active and 5,800 pill to de-activate the swtich. Call if you have any questions. 704-948-7280