Summary

This is a model of the Apollo A7L spacesuit neckring (to attach the helmet; outer diameter 270mm). Multipart design due to enable:
a) production on printers with smaller base plates
b) printing with different qualities (i.e. the carrier can be printed with a higher quality than the other parts)
c) easy coloring of smaller parts
d) free positioning of the slider
First glue the upper and the lower ring together then glue the upper to the lower ring. Afterwards glue the carrier to the upper ring and attach the slider. After coloring the ring and all other parts glue them together as well. For perfect shape use two m2x3 slotted lenshead screws. Connection to the collar of the suit can be made with a 8mm hose clamp band.

Helmet pictures only added because of a comment below.