Nothing matches all of those filters.
The full range
Rockwool for propagation through to full hydro grows
Rockwool is spun mineral fibre, sterile out of the bag and consistent cube to cube, which is why it is the default medium for growers who want to remove variables. Grodan Transplanting Cubes (from £3.50) start seeds and cuttings, sized to drop straight into a larger Grodan Propagation Cube (£11.95) or slab as roots develop, without disturbing the root ball at any stage.
The pH soak that gets skipped too often
Fresh rockwool comes out of the pack with a naturally high pH, and skipping a pre-soak in pH-adjusted water around 5.5-6.0 is the single most common reason cuttings sit and sulk in rockwool rather than rooting. Give cubes a proper soak before use, not just a quick dunk, and they will hold moisture evenly rather than drying unevenly at the edges.
See propagation medium for other rooting options like Root Riot cubes, and hydroponic medium if you are moving cuttings on into a full hydro system once they have rooted. Free UK delivery over £60. Call 020 3488 0419 for advice on getting rockwool right.