10 - 5/8" & 1/2" Whistle Buckles (5 Each) For Paracord Bracelets 5/8" (Whistle - Flat) & 1/2" (Whistle - Contoured) Side Release Buckles 5/8" Whistle - 19mm Opening For Webbing or Straps - 1.9" Long, 0.87" Wide, 1.1" Wide At Whistle Tip 1/2" Whistle - 13mm Opening For Webbing or Straps - 1.8" Long, 1.07" Wide At Whistle Tip.