Martin Avanti I Square Post Canvas Holder Set Set of 4 additional Canvas (blocks) holders that only fit Avanti square post Easel #92-50404 Set of 4 additional canvas (blocks) holders that only fit Avanti square post easel #92-5040 Set of 4 additional canvas (blocks) holders that only fit Avanti square post easel #92-5040 Set of 4 additional canvas (blocks) holders that only fit Avanti square post easel #92-5040 Set of 4 additional canvas (blocks) holders that only fit Avanti square post easel #92-5040