Bowman manual traps have been in production since 1966. The rubber & rail designed for those manual traps used a 4BA screw and nut. To this day, we continue to make our rubber and rails with the same methods because, put simply, they work!
The 4BA spanner can be difficult to come across with metric spanners being more commonplace, therefore we decided to make our own.
Our 4BA spanner comes as a handy keyring with a ring loop and is essential kit for changing your rubber and rail.