I think I ' d avoid noise cancelling headphones in this price range . They will just be heavier , with no real benefits . The few headphones I know at this price are not pretty . the Monoprice 8323 for example . Sennheiser HD 202 II ? <| sep |> no , every single bullet takes away 1 resupply unit . So 7 bullets eat up an ammo crate . <| sep |> Elsevier ' s Referex collection has a very nice set of nautical engineering design books in it . They are not books of designs for you to build , but books about how to design a craft that meets your specs . If you do some searching I am certain you will find a torrent of information out there waiting for you . <| sep |> He ' s being truthful , not retarded . A life jacket saves against getting knocked out and drowning by rotating you onto your back when in water . A buoyancy aid is just that . An aid . Designed to help you float while help comes , but you still need to keep yourself upright .