To securely fasten to wood posts, OK Brand barbed fence staples will do the job. OK Brand staples are slice-cut and have plenty of holding power. The sharp points make them easy to drive into the wood and the barbs hold them securely in place. Made with high-quality commercial and class 3 galvanized wire coatings, this double-barbed, 8 ga staple is made to do the job right the first time and for a long time.