Hello -- In general, firmer mattresses can be a good match for back sleepers. There are two reason for this:

1. From a support standpoint, the job of the mattress is to hold your spine in its proper position. In general, when you're sleeping on your back, your body has fewer curves that need to be contoured in order to keep your spine in position (relative to sleeping on your side, for example). So, a firmer mattress with less contouring support can typically do the job quite well for a back sleeper.
2. From a comfort standpoint, lying on your back distributes your weight over a much broader surface area than lying on your side. This means that back sleepers tend to encounter fewer issues with pressure points, which frequently develop in places like your hips and shoulders. As a result, a firmer mattress with less padding can often provide sufficient comfort for a back sleeper.

That being said, we don't have a Plushness Score for this model, so it's hard to know how firm this model really is (the fact that it has "Firm" in the name is a rather imprecise and sometimes even unreliable indicator of how firm it really is).

Even more importantly though, the degree of firmness you're going to want is going to depend on more than just whether you're a back sleeper. Factors like pressure relief and comfort preference are going to play a role here too, as well as your weight and body shape. This is why we always recommend that you try a bed in person before buying it to make sure it feels good to you and that it really provides the support you need for proper spinal alignment.