The Hitachi (HiKOKI/Metabo HPT) 373656 is a genuine replacement panel sheet (A),specifically used in the following cordless framing and strip nailers :
Metabo HPT NR1890DCS: 18V Cordless 3-1/2" Plastic Collated Strip Nailer
Metabo HPT NR1890DR: 18V Cordless 3-1/2" Paper Collated Strip Nailer
HiKOKI NR1890DBCL / NR1890DBRL: Regional variations of the same 18V cordless nailers