New 12" x 35" Heavy Duty Hydraulic Thumb for Caterpillar Excavator. THUMB SHIPS IN 1 DAY! Standard features include oversized alloy steel pins and AR 400 steel structures highlighted by AR 400 steel tines with serrated edges. AIM thumbs are designed to work in coordination with existing buckets and attachments. Thumb folds up tight when not in use. Main Pin Diameter: 2.00. Cylinder Safety Factor: 4 to 1. Units are manufactured by AIM Attachments, who has been building attachments since 1970. If you have questions regarding specifications or require additional attachments please ...