Dust-proof idler procurement requires more than specifying roller dimensions and a labyrinth seal. This guide helps project buyers evaluate how seal geometry, bearing protection, contamination, moisture, load and operating speed affect conveyor idler reliability. It explains what to request from suppliers, how to compare labyrinth and contact sealing approaches, what to verify during sample approval, and which technical, quality and commercial information should be included in an RFQ before a bulk conveyor idler order.