Versatile, multifunctional Sport Plugs can be used as a passive-protection plug or replacement plug for Primos digital BTE or Boost BTE. To use as a replacement tip, pull the hock filter and cap out and insert the BTE acoustic tube into the PSP3 plug. For passive hearing protection, simply snap the hock filter closed for noise reduction rating (NRR) of 24db, or use as a noise filter with the cap open. Made in USA. Colors: Black, Clear.