Unique design, efficient, and widely used. 1) Sizes: NFST-20, 25, 30, 35, 38, 40 with diameter of 1.2MM.2) Packing: 3010pcs/box, then10 boxes/carton.3) Unique design, efficient, good quality, widely used.4) Made of Mid-carbon steel, an ideal substituted product for masonry nails. SizeToleranceL20MM~40MM-0.05MM~-0.1MMb2.3MM+0.2MMH1.1MM+/-0.1MMd1.2MM-0.02MMd1>/=1.2MM T Nail - High Carbon 1.2MM