Like http://www.thingiverse.com/thing:2063292 this is an upgrade to the Anet y-carriage with clearance for the y-axis motor and more stiffness than the original part delivered.
Outer dimensions are 219x219mm so should fit every printer with a similar design like Anet A6 etc.
I removed the option to mount only three bearings since the original P3Steel evolved in removing this option, so why would one add it again?
Since the distance of the holes on the P3Steel and the Anet for mounting the bearings and y-belt are different, i added mounting holes and cutouts for the original P3Steel parts.
All holes are designed as clearance holes.
update 17-03-02: received the frame today and will install it later. Be advised that you have to modify the y-endstop if you decide to not take the original bearings with their housing and you have to check if your y-belt tensioner does interfere with the carriage. If so, you have to print another tensioner before installing.