Straight Frame Extender trailer is a name for a flat trailer which extends when required to carry long loads. Straight Frame Extender trailers may also be called:
- Flat extender trailers
- Flat extending trailers
- Platform extender trailers
- Platform extending trailers
- Trombone trailers
Straight Frame Extender trailers are built around a central steel box beam which carries a second beam within. The inner beam extends telescopically and is pinned in an extended position.
Normally a Straight Frame Extender trailer splits a few metres behind the headboard, providing deck surface on both sides of the split, to enable secure loading and lashing of the burden.