T4 Replacement Tubes (white) are called T4 because they measure four eigths of an inch in diameter, about 12.5mm.
They have been used for kitchen lights, bookcase lights, cabinet lights and anywhere a small fitting is required.
We prefer the T5 as the technology is more advanced and they have been proven to be more reliable.
MFI have sold a lot of kitchens with Smilite fittings which use these tubes, we cannot source these tubes, if anyone knows where to buy them please let us know! We do have a 10w which just fits one of the Smilite fittings.
When you measure your tubes do not include the pins
There are many brands of lamp here are some of the more popular ones:
Omicron, Sector, Greenbrook, Eterna