Alpinestars Nucleon KR-1 Back Protector (X-LARGE) (BLACK/WHITE) The Nucleon KR-1 hybrid back protector incorporates race-oriented back protection CE certified Level 2 to the latest back protector standard. Superb ergonomics and ventilation features make this extremely lightweight protector ideal for street or performance riding.Back protection CE certified Level 2 to the latest back protector standard revision (prEN1621-2:2014).Featuring hard-shell vertebra