These are small plastic variable capacitors with a dual section 0-266pf these can be connected to give a total capacitance of 0-532pf.
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.
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.