Mavea 3/8" BSP to Compression Water Filter Head Fittings Kit.
This kit is for the older style heads that need adapters to go from a Metric fitting to a US fitting- 3/8 BSP x 3/8 Compression. The kit also includes the necessary washers to seal the fittings to the head. The color of the washers will vary.
A quick way to identify if you have an "old" head versus a "new" head is by color. The "old" heads have black connections for the fittings to be added, the "new" have silver.
Mavea updated their heads in 2018 to no longer require an adapter to go from metric to US. The current kit can be found here.
If you have any questions about what kit you needs, please email a photo of your Mavea head to firstname.lastname@example.org and we'll be glad to get you pointed in the right direction.