Many diaphragm and small vacuum pumps come with G BSPP intake and exhaust thread ports. These 1/2 Inch G to KF-16 fitting adapters convert "G" BSPP thread to a KF-16 flange which is more commonly used in the universal world wide vacuum market. This thread size is primarily used in Europe and Great Britain.

BSPP = British Standard Pipe Parallel (straight thread) and is often noted G, for example, G(1/2).

Adapter KF-16 Flange to 1/2 inch Male BSPP Thread (British Standard Pipe Parallel), Stainless Steel
Common Dimensions:
A = 1-3/16 inch (30mm)
B = 7/8 inch (21mm)
C = 5/8 inch (16mm)
D = 1-3/8 inch (35mm)

These KF16 adapters screw into pump inlet and or exhaust for easy connection to standard ISO KF or NW roughing line fittings.