Made of New Zealand radiata pine timber. Stainless spring steel wire AISI304, dia: 0.375. Eyelets: 2.5mm diameter and 4.5-mm long. Frames are stapled with 19-22 mm staple pines. 3-staples on each side of top bar and 2-staple pins on each side of bottom bar. 10-pins per frame makes it a nice and strong product. Full Depth frames are suitable for langstroth and flow hive respectively.