Please be aware that there are several versions of C&C grids available when you look online. Always go for the ones with 8 wires inside the metal frame (9*9), but even those are too wide for very young guinea pigs! You will have to protect your grid cage with higher correx/coroplast rims or perspex until your guinea pigs' heads can no longer get stuck.
You may find this picture here instructive when looking for grids online (copied with the kind permission of piggy pages fb community as the owner of the picture):

You may find this picture here instructive when looking for grids online (copied with the kind permission of piggy pages fb community as the owner of the picture):
