This is a Simpson Strong-Tie PAB5-24, Swan Secure Pre-Assembled Anchor Bolt 5/8 x 24-Inch ATR With 1-1/2 x 1-1/2 x 3/8-Inch Washer. PAB Pre-Assembled Anchor Bolt The PAB anchor bolt is a versatile new cast-in-place anchor bolt ideal for high-tension-load applications. It features a plate washer at the embedded end sandwiched between two fixed hex nuts and a head stamp for easy identification after the pour. â¢Available in diameters from 1/2" to 1 1/4" in lengths from 12" to 36" (in 6" increments) â¢Available in standard and high-strength steel â¢Head stamp contains the No Equal sign, diameter designation and an "HS" on high-strength rods Note: The image here is for the series. The actual item may not be an exact match with the image shown, but should be similar. See Simpson site for particulars.