Image Item No. Description  bslot01  Brick 1 x 2 without Bottom Tube, Slotted (with 1 slot) Catalog: Parts: Classic  bslot02  Brick 2 x 2 without Bottom Tubes, Slotted (with 1 slot) Catalog: Parts: Classic  bslot02a  Brick 2 x 2 without Bottom Tubes, Slotted (with 2 slots, opposite) Catalog: Parts: Classic  bslot04  Brick 2 x 4 without Bottom Tubes, Slotted (with 1 slot) Catalog: Parts: Classic  bslot04a  Brick 2 x 4 without Bottom Tubes, Slotted (with 2 slots, opposite) Catalog: Parts: Classic