These Zareba T-Post Polytape Insulators for 1.25 and 1.33 in. T-Posts help prevent problems from arising with your electric fence by keeping the polytape from moving on the T-post. The electric fence insulators are molded of heavy-duty polyethylene, and have a large flange that prevents arcing. The tape holder included with these black T-post polytape insulators unlocks for easy installation. Compatible with 1.25 and 1.33 in. T-posts. 25 total fencing insulators per package.