Brass Lens

I bought an old Sigma lens SLR Zoom has a bayonet mount with 3 bronze connections can anyone help.?

I know it's Pentax K I send an photo … Do not give any information on the lens. Lens is SIGMA ZOOM MASTER 1:3.5-4.5 35-70mm zoom Multi-coated 52mm filter thread.

Enjoyed with a Jessops store or similar. There should be one near you. Good luck. ps. Look inside of the lids. It could have initials printed on them. Ok, I know it's not a Pentax, but if it were, would have to "PK" stamped there. The idea? Good luck.

Brass Lens

Brass Lens