This is a awesome product! I was able to finish my laser machine . Some people say that the blocks are too loose, some are but they have adjustable screws to make them the right tension.
These are the Y axis rails for a 48 X 96 inch CNC Mill I'm building. I bought 4 rails took two rails, removed them from the base shifted the base by two holes and remounted it then I have two sets of 8 foot rails. and the bearings slide right across the TINY gap as if it were not there
jason mcdaniel 
