3/4″ CRUSHER RUN Specifications. 3/4″ 6" x 0", 6" CRUSHER RUN Specifications: 6" x 0" R3 RIP RAP Specifications: 3″ X 6″ R4 RIP RAP Specifications: 4″ X 12″ R5 RIP RAP Specifications: 4″ X 18″ R6 RIP RAP Specifications: 6″ X 24″ R7 RIP RAP Specifications: 12″ X 30″ R8 RIP RAP Specifications: 15″ X 42″ RAILROAD BALLAST