Frontier straws,I have & use them on occasion,both types.You have to make sure to spit out the 1st few mouthfuls because,I failed to heed that advice my 1st time,& Swallowed a bunch of grit,which in turn made me Gag,& Almost puke!It's funny when it happens to someone else in a NON-survival moment,could be tragic in a Real survival situation when water is scarce!