The present invention concerns a transit for leading cables, pipes or wires through a partition in a sealed way. The transit comprises a sleeve (1) and a seal (2) to be received inside a central through opening of the sleeve (1). The seal (2) comprises a base part (7), a front fitting (9) and a rear fitting (10), which front and rear fittings (9, 10) are placed at opposite ends of the base part (7). The base part (7) of the seal (2) is made of a compressible material, whereby the front and rear fittings (9, 10) are arranged to be moved towards each other in order to compress the base part (7) of the seal (2). The sleeve (1) has at least one inner groove (4) at one end of the sleeve (1), which inner grove (4) is designed to receive one or more protruding parts (12) of the front fitting (9).