Neat, 'Infanterie-Sturmabzeichen in Silber' being a maker- (ie. 'F.L.L.'-) marked (and somewhat converse- ie. vaulted-) 'solid-back'-example by the maker: 'Friedrich Linden' as was executed in silver-coloured, zinc-based metal (ie. 'Feinzink')
This example is a neat - albeit clearly worn, typical maker- (ie. 'F.L.L.'-) marked award: it has a 'typical integrated' catch and/or hinge (-set-up) as is more often encountered with IABs by this specific maker. I deem that this example can with certainty be determined as a 'later-war-period-variant' that can be attributed to the maker: 'Friedrich Linden' (ie. 'F.L.L.') as based in the town of Lüdenscheid. The badge was with certainly issued and comes in a moderately used- ie. worn condition (as can be seen on the pictures). It was - I deem - not cleaned nor polished but retains most of its silver-coloured finish as can be seen on the pictures (something that is more often seen on these later-war-period 'FLL'-examples). The pin and/or catch (ie. set-up-) are of course fully functional and/or present (they are both in pristine condition). The piece - which originates from a private-household where it was recently found - shows as stated above wear, age and/or staining but is nevertheless still an attractive example. Simply an attractive 'solid-back' IAB-variant that is I deem accordingly priced!