In an excellent condition a US Army M5A1 bayonet with M8A1 PWH scabbard
The bayonet is marked U.S. M5A1 and maker marked MIL PAR COL under cross guard, which stands for Columbus Milpar & Mfg from Colombus (Ohio). The scabbard is marked U.S. M8A1 PWH, which stands for the Pennsylvania Working Home (for the Blind). It was made between 1965-69, which places it used during the Vietnam war.
Blade length = 16.8 cm
Total length = 28.9 cm