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. 

WARNING:  Don't forget 4 wood screws to fix ear brackets.