The #16B A1 attachments will fit any British Standard 16B roller chain. The A1 attachment has 1 bent tab with a single hole.
16B A1 Attachment Connecting Link Dimensions
Pin Diameter (d2):8.28mm
Link Plate Thickness (T):3.10mm/4.15mm
Tab Width (G):19.1mm
Attachment Width (W):36.30mm
Width To Center Hole (F):25.40mm
Attachment Hole Diameter (d4):6.4mm
Connecting Link Clip Type:Spring Clip
Connecting Link Installation Tips
Spring Clip Connecting Links: The spring clip should be installed where the opening is facing away from the direction of travel. This will help prevent the spring clips from coming off. Like shown in the diagram to the right. Careful not spread the clip opening too far apart. This can make the clip more prone to falling off.
Cotter Pin Connecting Links: Cotter Pin Connecting Links The cotter pins pin legs should be spread about 60° apart. Like shown in the diagram to the left. Never reuse cotter pins that have been taken off. Never use commercial cotter pins as these are usually not hardened.