TR3, 4, 4A, 5 and 250. Chrome Nut securing wheel box to Jet support block and the bulkhead. The 8 sided nut 17H8769 used on TR6 can be used as an alternative. See below.

This part is listed on the following pages of the website, where further information and background reading may be found.

This part appears on the following Triumph Catalogue Plates