A pair of identical reversible steel telephone Lineman crimping tool pliers marked M.Klein & sons. Overall length in closed position : 29 cm. Also the mark includes Est. 1857 and Klein Tools, along with a man climbing a telephone pole. Both pliers are in mint condition. Alexander Graham Bell invented the telephone in 1876. M.Klein & sons apparently started making tools in 1857. The present pliers therefore could be dated end 19th, early 20th century.