These are small plastic ( Poly ) variable capacitors with dual 3-60pf and 6-141pf sections. You can connect the 60pf and the 141pf section together for 9-201pf if you want.
Screws and washers for the variable capacitor are available in two lengths: 5/32″ (4mm) and 3/16″ (5mm). The shaft and two mounting holes are both tapped metric M2.5.
This is the variable capacitor used in our Crystal Radio and MK484 radio kits.
CAUTION: The internal parts of the variable capacitor can be damaged easily if the screw enters the variable capacitor too far. Please check for clearance.