Outdoor Research Lightweight Pack Cover

Very waterproof, snug
Have been using rain pack covers since 1977. OR's HydroLite fabric is the most durable of all coatings I have experience with. External side of the material does not absorb water like all my other covers. Lightweight. Can shake off most water before stowing or strapping on pack when not needed. Color is visually unobtrusive. Sizes are larger than you would expect: XL fits my old 8000 cu.in. pack w/ gear attached [could almost serve as an emergency bivvy]; L will fit the backpacker's avg large pack w/ gear attached. Negative comments: (1) elastic drawcord can get a little 'hung up' upon cinching, and (2) no drain hole at bottom, so water can potentially pool. I purchased the M, L & XL sizes to replace old covers and accomodate all my packs.

Packs light, hold tight
Love it. The XL is only 7.8oz (221g) and fits perfect for my 5000L pack. I even have a few externally strapped items (first aid, water shoes, etc.). The HydroLite fabric is really light its taken a decent beating so far. The elastic drawcord works nice since your never going to find a cover that molds the entire pack. Highly recommended. There is nothing worse then being soaking wet. Most packs repel light rain, but start to absorb a little during heavy down pours adding additional weight.