Dust Case with Elastic Band Dust Cover Protective Case Lycra High Elasticity Speaker Case Slip Sleeve Compatible with JBL PartyBox On The Go Portable Party Speaker. The dust case is specifically designed to provide a snug fit and comprehensive protection against dust, dirt, scratches, and other damage, thereby extending the speaker's lifespan. Made from soft, high-elasticity Lycra fabric, the speaker cover offers a tailored fit, excellent wrap-around protection, and a comfortable grip.