Class pack of 5. Consists of 5 plywood beams with grooves. Supplied with 4 fulcrums & 40 metal blanks 25 mm square. 
Supplied as kit for eight pupils and consists of five plywood beams 600 x 44 x 3 mm graduated every 38 mm and with groove across its centre to locate the fulcrum point. Also included are four fulcrums 32 x 32 x 64 mm and 40 metal blanks 25 mm square. The masses of the blanks are matched to + 1%.