Extra narraw means more container loading capacity to save big unit cost. Mattress thickness 60-80MM Same container loading capacity with or without mattress. TF00W is mid leg version (8cm wood legs). 

1. Very comfortable for 6cm mattress because no cross bar in body area ,and deck is held by helical springs. 
2. Now we offer air breath and fire-proof deck material,this make seat and sleeping more comfortable. 
3. Partly assembled verison is easy to assemble like relciner mechanism, which can load more than 1000units per 40HQ. 
4. Same loading capacity with or without mattress inside. 
5. Whole slats or 2 slats,4 slats mixture available. 
6. U-bar is necessary if people in some market like to sit in open bed.