A whistle is priceless when needed,wrap some rubberbands or innertube around it for grip,&/or xlnt waterproof tinder.By the way,You have a Very well thought out kit,I hope you don't need it but glad you have it! Sorry about that,I must have had a brain frrt,I see you have some fox 40's listed,the rubberbands/innertube are very handy,multi-use & lightweight,& Thats it! Cheers!