The GunBroker listing does not give any information as to length nor width.
Looks like a standard British "StenGun" recoil-spring.......(?)....but also looks too short to be fot the MG34 or the MP44 series. I know that it is not for the MG34/41 (MG34S) as they were "braided-wire" like that of the MG42 (but of different diameter/length/number of coils.