I love my 100% bamboo jersery trifolds as well.
They are 2 layers bamboo, stitch and turned edges, could be trifolded or folded in half lengthways, or (my favourite) folded into a square for the front of the nappy. They are also good for boosting a fitted because the bamboo is lovely against skin and don't add hardly any bulk.
When mine arrived I thought crikey these can't be inserts they are way too thin (that's how trim they are) but they are great. Mine dry in the same time as all my other inserts.
They are still really soft and white after lots and lots of washes.
Mummy to a gorgeous big boy and a darling wee girl