HEAVY DUTY-Featuring an L6-30P to L6-30R twist extension cord with SJTW 10GUAGE 25FT 30A 250V TWIST LOCKING DESIGN the plug Compatible with any generator equipped with a L6-30 receptacle.And the lock is designed to prevent falling off in bad weather. THE MATERIAL is waterproof, the temperature resistance level can reach 105 with the FT-1 level. the cold resistance level is -40, indoor and outdoor can be used all year round. THE Certifications is UL.The number is E257089 CUSTOMER SATISFACTION & PRODUCT QUALITY ARE OUR FIRST PRIORITY- if you have any question about our products and service, please feel free to contact us, we will reply within 24 hours