Polylok 30130-TL 4" Extend 'N Lok - We look at problems as opportunities. We heard from many of our customers that they love our filters but they were having difficulty installing them into existing tanks. Why? Because the inlet or outlet pipes weren't long enough to accept the filter tee or baffle. Our Extend & Lok™ is a simple, easy to use solution that can extend the inlet or outlet pipe and make filter and/or baffle installation a snap.