For Metric gas adaptors
change the imperial size in the part number to the metric equivalent.
For example:from 1/4 inch to 6mm
Imperial = LFGA100-0.25FVCR
Metric = LFGA100-6FVCR
Imperial and Metric equivalents are the same price.
LFGA063-0.375FVCR Gas Adaptors Female VCR