he development of the Orlík model was initiated by the Ministry of National Defence in the middle of the 60s. Besides reliability and precise tick, the watch was required to meet the following criteria: higher shock resistance, water tightness at least for 5 atm, fluorescent hands and indices on the dial and revolving ring, anti-reflexive surface treatment.
 
In order to meet all these requirements it was necessary to find not only a suitable design and technological solution but also suitable materials. The casing, revolving ring winding wheel and screwing bottom was made from special stainless steel Phonix MAZ with mat sand-blasting to prevent reflection of light on the surface.
 
The water tightness of the casing corresponding to a testing pressure of 6 atm was ensured by utilizing rubber sealing for the bottom and for the glass. The design solution of the water tight winding wheel was highly interesting as it was not screwed on unlike similar watches produced in the world. This part was very complex, it had a remarkable number of components: eight altogether!
 
The Umaplex glass was 2.7 mm thick in order to resist to high pressures. The black matted dial with grey-white printing had 12 symbols from luminescent radioactive paint, as well as the hands and the point on the “12“ of the revolving ring. The application of the luminescent paint was in charge of the Institute for Research, Production and Utilization of radio-isotopes in Prague.
 
The movement of calibre 50 with eccentric second hand was specially adjusted before encapsulation in the housing in order to keep strict requirement on chronometric characteristics of the watch. The order in the total number of 600 pieces was produced and delivered to the Ministry of National Defence in 1968. Each watch was numbered on the bottom and placed in a wooden box.
Limited Edition of PRIM Orlík 55 l.e.
 
The design is almost equal to that of the original model from which the design of the dial, hands and revolving ring was taken over. The casing was produced under total observation of the existing technical documentation and even the mechanism of bidirectional locking was inspired by the original model. Unlike the original watch the winding wheel is of screwing type and sealed with two O-rings. The casing, revolving ring, winding wheel and screwing bottom are produced from chromium-nickel-molybdenum bearing austenitic steel 316L which has increased resistance against corrosion in a chemically severe environment and against a temperature up to 350°C. The quality of the material is testified by the fact that the material is certified for surgical application, e. g. for the production of articular implants.
 
The revolving ring is graphically completed with a unique technology of partial surface hardening to give the material not only high resistance against abrasion but also the characteristic black matted colour and fine surface structure. The design of the locking mechanism is built on a sapphire bearing (three sapphire balls strutted against the ring on stainless spring segments). A qualitative modification in comparison with the original model is the application of anti-reflection sapphire concave glass of 2 mm of thickness. The scratching resistance of this type of glass is substantially higher than with the original Umaplex glass.
 
The watch is equipped with a mechanical movement Prim calibre 74 (base:
ETA 2895-2).
 
* mechanical movement with automatic winding
* 27 rubies – bearing stones
* oscillator frequency of 28,000 swings per hour – 4 Hz
* shock-resistant housing of balance wheel
* rotor is placed in a ball bearing of 7.6 mm of diameter
* mechanism is equipped with micro-regulation – fine tick regulation
* precision of tick is regulated to meet the requirement for a maximum of 10 seconds of daily aberration
* guaranteed operation reserve of 44 hours – in practice, a reserve of 50-52 hours is achieved
Function:
* analogue display of time – hour hand, minute hand, eccentric second hand, numeric date
 
The rotor of the movement is individualized. It bears a ordinal number of the watch in the series in the format e. g. No. 11/55 and the name of customer for whom the watch was produced. The identification of the watch with an ordinal number in the series is marked not only on the rotor but also on the casing (between foots), on the crown and also in the certificate. The view of the mechanism and the individualized rotor reveals a special screwing bottom which combines a stainless screwing component with a sapphire glass look hole.
 
The water tight design of the watch corresponds to the requirement on testing cycle of 10 ATM (overpressure/underpressure), i. e. 100 meters of water column. Nevertheless, a water tightness of 50 meters is guaranteed for the watch. It should also be admitted that for hygienic reason we could not use the original radioactive luminescent paint. This paint was substituted with an expensive application of multi-layer powder reflexive paint which results in a more or less the same luminosity of the indices.

PRIM Orlik 55 LE
 
55,000CZK = 2,427.18 USD