This prismatic fluid compass looks like a British MK3 Compass. There are differences. The fluid container is completely closed. No possibility to fill it in case of bubbles. It's a large compass, larger than the MK3. It contains a clinometer (watch the steel bullet)
This compass was also produced by MOM (Magyar Optikai Művek, Hungarian Optical Works) in Budapest.
If you are the site owner, please renew your premium subscription or contact support.