Brass referee whistle for outdoor activities and survival equipment The whole made of high quality brass (including copper ring), novel design, fashion small, full of materials, exquisite technology.<br> After polishing through advanced pickling process, can effectively protect the whistle, not easy to scratch, and oxidation resistance.<br> Scope of application:outdoor survival, self- life saving, player collection, etc.<br> Frost and heat resisting and long service life. Suitable for training pets, , birds, outdoor survival etc.<br> Made of high quality material, more durable. Easy to use and operate.<br> The interesting thing about brass is that it changes color process due to oxidation. Different colors will have different visual aesthetics. After oxidation, you can use sandpaper to polish or wipe with toothpaste, which can make the copper color return to the most initial new state.<br> Colour:yellow<br> Material:brass<br> Size:1x1x4.7cm<br> Package Contents:<br> 5 x brass whistle<br> Only the above package content, other products are not included.<br> Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.