The Petri GX-1 exists in two flavors, both rebadged Cosina 35mm SLRs accepting K mount lenses. The version with a self-timer is the Cosina CT-1A, some adding a raised, ridged "GX-1" badge. A restyled model (with a handgrip but no self-timer) is the CT1G. Only the second was sold in a blue version alongside the usual black.
A Petri GX-1 Super also exists; and likewise rebadges a Cosina SLR, the CT-1 Super.
All are fully mechanical, manually operated cameras which only need the batteries for the operation of the lightmeter.