ten seats, of which four are for the commander and his staff, four are for the radio operators and two are for the vehicle's commander and driver. The staff compartment has a collapsible table, a second small table for the commander, two hammocks and three ladders. An emergency escape hatch is provided in the floor of the vehicle and the vehicle has thermal insulation. Specialized equipment consists of KN-2 and KP-2 navigation devices; an AB-1-P/30 1 kW generator (located on the rear engine deck); R-105, R-105U and R-113 VHF radios; a R-112 HF transceiver, a R-311 HF receiver; a collapsible 11 m mast antenna for the R-105U; a light 10 m telescopic mast for the R-112; a R-403BM relay-set; R-120 intercom and a P-193A 10-line field telephone switchboard with six TAI-43 field telephones and four cable reels, each with 600 m of two-wire cable. The navigation system includes a gyro course indicator and course plotter (the former indicates the vehicle's course, the latter plots it on a rectangular co-ordinate system). Some vehicles have different numbers of stowage boxes in different arrangements on the rear engine decks. Some vehicles have a second generator. BTR-50PU with a longer nose section. BTR-50PU-2 – An improved version with more modern radio equipment, most probably the R-123 and the R-130M. It is externally similar to the BTR-50PU, but has a portable generator located immediately behind the troop compartment. BTR-50PUM – A modernised variant, it is equipped with a large AMU telescopic antenna mast and R-123 (3×), R-130, R-326, R-405D and T-218 radios. This model has a square antenna stowage box on the right front side of the hull. BTR-50PUM-1 (1972) – latest model with a crew of up to 8 and fitted with the same radios as mounted in the R-145BM (BTR-60): R-111 (2×), R-123MT, R-124 and R-130M. MTP-1 (mashina tekhnicheskoj pomoshchi) – A technical support vehicle with a raised troop compartment and a light crane. Polyesye – A civilian version of the MTP-1. Belarus BTR-50PKM – An upgraded BTR-50PK with a UTD-20 engine developing 300 hp (224 kW), new steering, brake systems and driver's optronics. MTP-300T – Technical support vehicle, fitted with a manipulator, a universal welding machine, towing and lifting gear, a workbench, spare parts etc. Bulgaria R-54 - A planned Infantry Fighting Vehicle variant, with a 23mm cannon. Complement for a 3-man crew and 9 passengers R-82 – An improved BTR-50PU command