{"product_id":"rc-lock-assembly-knob","title":"Rola-Chem Lock Knob Assembly for RC303\/305\/307 Peristaltic Pumps","description":"\u003cp\u003eThe Rola-Chem 523408 is the lock knob assembly used on the RC303, RC305 and RC307 peristaltic chemical feed pumps. It is the knob that clamps the roller housing cover closed over the pump head.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy it fails\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe knob comes off every time the squeeze tube is changed, and that is exactly when it gets cross threaded, over tightened or dropped. Once the knob will no longer draw the cover down tight, the tube is not pressed properly against the rollers and feed rate falls off or the head leaks.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCheck the model first\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThis knob is listed for the RC303, RC305 and RC307. The source listing specifically states it does not fit the RC252 or the RC301, so confirm the model on the pump label before ordering.\u003c\/p\u003e","brand":"Rola-Chem","offers":[{"title":"Default Title","offer_id":48634719994068,"sku":"ROL-451-9000","price":10.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0801\/9568\/2516\/files\/default_00db8908-5487-435c-ba01-84e72bbeb32d.jpg?v=1788836563","url":"https:\/\/www.activepoolsupply.com\/products\/rc-lock-assembly-knob","provider":"Active Pool Supply","version":"1.0","type":"link"}