I will put the many different liner systems I found installed in civic helmets on this page. I have a few more to add. Work in progress.
Below some of the most observed the civic liner band rivet combinations.
M34 with thinner split pins as those you see on combat helmets , the rivet head is smaller too , 1 cm. Combat helmets rivet heads are around 1.3 cm.
M34 (bulgy salt shaker vents) with similar small 1 cm rivet but using a rivet without legs. A permanent solution which does not allow the rivet to be replaced easily.
Here we see an M34 with dome rivets (mostly observed on DRK helmets)
This is an M35 beaded helmet with standard combat helmet rivets. (and washer)
Another beaded helmet , this time an M42. Regular standard combat rivet but no washer.
Liner with leather in the back glued to the rear tongue. Often paired with a rollerbuckle chinstrap riveted around one D ring and using a clasp on the other side. Helmet shown is a medium weight Edelstahl helmet.
Liner with leather in the back stitched over the rear tongue. A variant of the liner above. Often paired with a rollerbuckle chinstrap riveted around one D ring and using a clasp on the other side. Helmet shown is an M34.
6 tongue liner with rear seam stitched and size stamp on one of the front tongues. Cork spacers are used to make the helmet wearable for a smaller head size. The helmet is a size 66 which normally fits a size 58/59 liner. This one is a 57. Helmet shown is an M35 beaded Quist.
This 10 finger liner is again a little bit different than the ones posted above , it sits in an early M34 shell ,notice how the rear seam runs across the length of the tongue.
Here’s another rear seam stitched liner , note the sweatholes punched in the front and the more glossy leather. The helmet is a beaded M40.
Another liner with bigger sweatholes to the front and different rear seam stithing. The shell is an M34 with bulgy vents.
This leather looks a lot like the one used in M31 combat liner system with the 5 holes in each tongue. The helmet is an M34.
Another example of the M31 style leather but with sweat holes punctured in the front.
Three pad world war 1 style liner. In a Himmler style shell.
Another variant of the WW1 style liner in an Edelstahl medium duty helmet.
This liner is made out of cloth and is consider a later war liner. This one sits in a three piece gladiator shell.
Here’s another cloth liner with a plastic chinstrap in an M42 beaded Luftschutz shell. Note the extra sewn in flaps which are not part of the standard liner.