Spanish to English Other Furniture / Household Appliances Heater parter

Hi,

I'm translating some product descriptions for an online retail site from Spanish for Spain to British English and am having trouble with a phrase. The product in question is a part for a heater, but I'm not sure what it is unfortunately. Here is the full product description for context:

'Membrana Calentador BERETA 65mm.'

It can be found at the following link:

https://www.amazon.es/dp/B00X68MANS

Having done a little research, I'm not 100% sure about what this is meant to be referring to (or whether the Spanish is particularly great in the first place!). Can someone help please?

Many thanks!