The Crosby model A-339 (1/4") is a forged alloy steel Clevis Sling Hook designed for use with 1/4-inch (7 mm) industrial chain slings. This model is typically categorized under Crosby's Grade 80 / Spectrum 8 lifting components. Note that newer production iterations are often cross-designated or upgraded to the Grade 100 A-1339 or L-1339 series.