DMM Big Dan SG Carabiner. 
 
Versitile and very strong boasting 50kn. This is a must in any arborists kit.
 
Technical Information
(MBS) Minimum Breaking Strength (kN)50
(MBS) Minimum Breaking Strength (lbf)11240
Gate opening gap (mm)27
Gate opening gap (inches)1 1/8
FinishZinc plated
Weight (grams)335
Weight (ounces)12