Petri's late M42 screw-mount SLR — the FTX, TTL metered, 1976.
The Petri FTX was a 35mm film SLR made from 1976 and, unlike the earlier Petri-mount bodies, it used the M42 screw mount. It appeared late in Petri's history, after the company's financial troubles, and the switch to M42 gave it access to the wide pool of universal screw-mount lenses.
It is a single-lens-reflex camera for 35mm film on the M42 screw mount. The FTX used TTL metering and a focal-plane shutter, operated in metered manual. Being an M42 body, it accepts screw-mount lenses from many makers, which is a practical advantage over Petri's proprietary-mount cameras.
It suits users who want a Petri-badged body that can take common M42 lenses rather than the scarce Petri glass. The universal screw mount is its main draw, making it easy to fit affordable lenses, though the body itself is a budget design.
On the used market the FTX is uncommon but its M42 mount eases ownership since screw-mount lenses are plentiful and cheap. Check the foam seals and mirror-damper foam, confirm the shutter fires at all speeds, and test the meter with an appropriate battery. Inspect advance, rewind and screen, and note that while the lens supply is good, Petri body build and repair support are limited.