Secure commercial aluminum and steel doors with the Prime-Line J 4516 Flush Mount Extension Bolt. Designed for use on commercial door applications, this extension bolt provides a dependable method of securing inactive door panels by locking them into the door frame at the top or bottom. Commonly used on storefront, office, commercial, and industrial doors, it helps maintain door security while preserving a clean, low-profile appearance. Constructed from durable diecast materials with an aluminum finish, this flush bolt is engineered for reliable long-term performance. The recessed design installs within the door edge and features a flush-mounted operating lever that raises and lowers the bolt without protruding beyond the door surface. The adjustable extension rod accommodates installation requirements with a length range from 8 in. to 10 in., while the threaded nylon tip helps provide smooth engagement and dependable operation. This extension bolt includes a flush bolt guide and installation fasteners for a complete replacement or new installation solution. Whether securing the top or bottom of an inactive door panel, this flush-mounted bolt offers discreet security and professional-grade performance. Compare dimensions and installation requirements with your existing hardware before purchasing to ensure compatibility.