Turns every category page into a proper faceted search. Shoppers narrow results with a dual handle price slider, attribute and option checkboxes (colour, size, and any option you sell), manufacturer and stock availability — and the product grid refreshes in place without a page reload. Every selection is written into the address bar (?filter_price=10-50&filter_manufacturer=1,3) so filtered pages can be shared, bookmarked, linked and crawled by search engines. Result counts next to each value are recalculated live from the products actually in the category, so shoppers never land on an empty page. The sidebar is injected automatically through OpenCart events — no theme edits, no core file changes — and falls back to a plain GET form when JavaScript is unavailable.