Please follow all NFA laws. Modification in any way of dry storage cups without an approved tax stamp could be considered a felony. Posted by Doug T. on Jan 13th 2022 This tube arrived very quickly. The materials, finish and machining is excellent. I would highly recommend these to anyone. https://solvent-trap-kit08642.illawiki.com/953357/solvent_trap_tubes_keine_weiteren_ein_geheimnis