See labeled image for components. Extensions may need to be shimmed for a tight fit. O-Rings; 2 x "130" or "30" - OD:1.750" ID:1.625" T:0.0625" & 2 x "129" or "29" - OD:1.625" ID: 1.500" T:0.0625" Springs; 8 x "G2 Pilot Gel Roller Pen Springs" UPC: 072838310576 Alternative ODMax:0.240" IDMin:0.160" MinCompLength:0.310" MaxL:0.490" Use 1.75mm filament to pin components in place.