There is a wide range of dry bags on the market. For niche applications (lashing on the back of motorcycles or kayaks) my preference is for Enduristan’s Tornado series as they are thoughtfully designed, light weight, high quality, and the webbing loops/straps allow you to cinch down the load without relying on friction alone to hold the bags in place. I‘ve looked at other brands but none offer the same advantages. Besides that, I live in Switzerland and it’s good to support local companies.