The Revival Systems weightlifting blocks are made from precision cut smooth plywood with reinforced internal construction to give the lifter confidence in there equipment, also with the raised edges on the  blocks it stop the bar from rolling off. 
 
to save on space all blocks can be stacked on top of each other when not in use making them more viable for places with limited space.
 
individual block heights:
tier 1 : 6cm 
tier 2 : 15cm 
tier 3 : 30cm 
tier 4 : 38cm