Brass compression fittings. BS 864-2:1983 or BS EN 1254:1988. They conform to both these standards apart from marking: a fitting conforms to the standards with which it is marked.
https://www.bes.co.uk/28-mm-compression-olive-brass-20387/39968Compression Olive - 28mm Brasshttps://www.bes.co.uk/media/catalog/product/2/8/28-mm-compression-olive-brass_min_20387_P_1.jpg0.240.24GBPInStock/Pipe Tube & Fittings/Pipe Fittings/Compression41671241424145<p>28 mm compression olive.</p><p>Brass compression fittings. BS 864-2:1983 or BS EN 1254:1988. They conform to both these standards apart from marking: a fitting conforms to the standards with which it is marked.</p>BESt range00https://www.bes.co.uk/media/catalog/product/2/8/28-mm-compression-olive-brass_min_20387_L_1.jpg5056198111566add-to-cartfacet_type:Olivespecial_price:0.240000cat_multi_facet_l1:Fittingsmore_sizes:20382,20383,20384,20385,20386,20388,20389,20390products_related:7623,9570,8199,16444,23208,7308,7389,7550,21112,19494,23366sku:20387FittingsOlive20382,20383,20384,20385,20386,20388,20389,203907623,9570,8199,16444,23208,7308,7389,7550,21112,19494,23366203870.240000No{"Type":"Olive"}BESt rangeBrassMetric28 mm