'Tru' (short for Through) and 'Butt' (or rail) are the designated connection points for tubes in a fence fitting. In the Tee example depicted on the left, the 'Tru' indicates the location where the tube passes through the fitting, while the 'Butt' indicates where a tube terminates in the fitting.

However, for the DF X Fixed Cross, the 'Tru' is replaced with 'Post' while still representing the through connection. If you are uncertain about which connection corresponds to each point, particularly for fittings that join tubes of different sizes, please do not hesitate to contact us for further clarification.

OD short for Outside Diameter and NB meaning Nominal Bore, are measurements used for hollow tube such as those used for fencing and scaffolding.

OD refers to the diameter of the outside of a tube. We refer to this using milimeter measurements such as C42mm or D48mm.

NB refers to the diameter of the hollow inside of a tube. It is traditionally refered to using Imperial measurements such as 1 & 1/4", or 1 & 1/2" or using NB such as 32NB and 40NB. Older tube and fittings was often made with these measurements in mind.

You can find a table with the common size comparisons under our "Size Guide" at the top of the page, or call and talk to a member of our team for assistance.