Features: In the grinding block glue on the 600 h-ead sandpaper arc polished, and then polishing the special s-ilk polishing, conditions can be re-use the crown file reshaping. As different guitars require different radian polished blocks, acoustic guitar generally use 12,14,16 arc, electric guitar generally use 10, electric guitar generally use 9.5. Minisize lightweight,itisportable space-saving. Madeofsuperb material,long-lasting endurable. Make your l-ife be full of sound and colour. Nicel-ifeassistanceforyou.