They assure perfect watertightness (IP-X7) for cable passing. They allow the cables to pass without disassembling possible end connectors. Edgeless shape for higher resistance and to avoid possible blocks for the line. Threaded holes for easy assembling and numberless disassemblings. Every item is supplied with a choice of pre-bored or to-be-bored seals for the utmost easiness and flexibility of use. Cable diameter - 4-9 mm, max. connector diameter - 21 mm.