For full specifications with this bag (already hell of a bargain at original price), which would normally cost around £100 (not to mention the brand being the most luxurious) with the properties for this to not be false savings, I'd recommend this source from the manufacturer:https://marmot.com/products/details/womens-trestles-15
You won't find any other sleeping bag for this price (others in this bracket offer comfort at 0 Celsius from less technical, established brands) that's from such a bespoke brand and of high ratings technically.
AKA: I AM AMAZED AT THIS VALUE! This could endure a severe Winter abroad and easily any weather in the UK! As someone very into technical equipment for hiking/mountaineering/trekking/camping, I'm still dumbfounded at this deal myself.