The Northington 2000 Pocket Natural Mattress from Rest Assured is a beautifully natural wool, cashmere and silk comfort fillings mattress, with a luxurious smooth damask cover.
Damask is a woven fabric, so I'd expect it to lie smooth under a sheet and run a bit cooler than a lot of knit covers I see. Owners like the plain, smart look of it, though a couple wish it wasn't so white because marks show.
The comfort layer is comfy, springy and highly breathable while being Hypoallergenic and free from foam and chemical treatments for a healthier sleep. This comfort layer features 100% natural cashmere, silk and wool fillings.
With tufted wool, cashmere and silk over the springs and no foam anywhere, on paper you get that buoyant, natural fibre feel rather than the slow sink of memory foam. Owners describe much the same, 'pretty firm but with just the right amount of give' in one review. Several who came off memory foam say they sleep cooler on it, though a couple found the wool made for a warmer bed.
Worth saying though, if you love that deep hug and pressure relief you get from foam, this won't give you that same 'moulded' feel, it stays more on top of the mattress.
The support layer is made up of Pocket springs which are created from separate pockets that each contain a tightly wound spring, this provides a multi-directional support to give you the ultimate comfort and support.
Those 2000 springs are zoned to put extra support under your back and hips, so a build like this should support you evenly instead of acting like one big bouncy unit. Couples bear that out, with several reporting no roll-together and no disturbance when the other one gets up. Owners split on the edge. One says the support 'is there right to the edge', another calls it 'a bit squishy on the sides', and I'd expect some dip when you perch, which is pretty normal for a plusher natural-fill top.
Each spring can be individually tensioned to suit your weight and body shape. The Northington 2000 has over twice as many springs as the original Northington pocket mattress making it feel like you are sleeping on air.
I wouldn't go as far as 'sleeping on air' myself, at 29cm deep, and heavy enough that owners complain about turning it, it's still a substantial mattress, just with a lighter, more responsive top than foam. Also, natural fibres like wool and cashmere can settle a touch over time, so I'd be rotating it regularly, and if you're a lighter side sleeper you might find it a bit firm through the shoulder unless you go for a softer tension.