Entrance / Exit Seal for Tunnel Boring Machine is a kind of seal to proteck tunneling machines. It is made of Rubber, and middle has an empty hole. So it is also called balck eye seal. The out diameter and inner diameter is made as tunneling machine model requirement, and also there are holes, each 5 degree has one hole to fit it one the tunneling machine.
Inner support: interwire with nylone wire and cotton wire
Thickness: can made 10mm, 20mm and 30mm thickness
Inner diameter and outdiameter: made as tunnel requirement
Note: for 10mm thickness, there is no water drop at the edge of circle.
Package: each one is packaged by plastic film first, then wooden box which fit for ocean delivery