The Czech Army bought three Carden-Loyd tankettes and a production license for them in 1930, eskomoravská Kolben-Dank building four copies that same year as prototypes for future orders. The Carden-Loyds were evaluated during the Fall maneuvers and revealed numerous problems. The crews had very poor vision through the narrow slits, the machine gun had very narrow fields of fire and the crewmen had a difficult time communicating. Further more they were slow, underpowered and often broke down. One of the P-1 prototypes was rebuilt to address these issues with additional vision ports in all directions, internal ammunition storage and the gunner's machine gun had its field of fire increased to 60°. It was extensively tested during 19312 and a few other changes were made as a result. The armor was increased from 6 to 8 mm (0.24 to 0.31 in) and from 9 to 12 mm (0.35 to 0.47 in) and a fixed machine gun was added for the driver. Two of the other prototypes were rebuilt to the same standard and all three were officially accepted by the Army on 17 October 1933. The other prototype was eventually given to the Shah of Iran as a gift. The order for seventy was placed on 19 April 1933, all being delivered by October 1934.[4]
The incredible noise of the top run of track scraping along the return rail was also a major problem. Most countries who rebuilt the CL tankette replaced this with return rollers.
The Vz.33s were hardly more useful the original CL tankettes and were assigned to border guard units after initial troop trials.
