These specialty tines fit Husqvarna and Bluebird Tow behind aerators; Fits Bluebird,Husqvarna Replaces # 7572 Tow Behind TA-10, TA-12. TA-36, & TA-48 Aerators  We make our tines from special tool steel and heat treat for longer life. Highest quality around. Box of 30 for $180.00 as eBay charges freight for a full box, they cannot calculate by each piece. 90+% of orders are from repeat customers