These concrete dobies have grooves built into them to create a cradle for the rebar to set in. This can create many usable dimensions from one brick. For instance, the 3 x 4 x 3 inch combo has an outside dimension of 3 inches by 4 inches. With the two grooves this product will provide cover heights of 2 ½”, 3”, 3 ½”, and 4”. All our concrete spacers meet standard PSI specs and can optionally be customized to add more strength for your specific rebar reinforcement needs.
Application: 
On grade.
Cover Height: 
Multiple cover heights.
Features: 
Designed with multiple heights within a single unit.
Standard 4000 PSI (Additional strength available at added cost).
D.O.T. Approved (In most states).
Meets all requirements and qualifies as a CRSI Class 1 Bar Support.