To deconstruct fourth quarter, I think we saw about what a number of the other spine companies saw was this almost a whiplash effect. And we're seeing a bit of that now here again in the first quarter, where we had a backlog of surgeries throughout the early fall. Then we saw October, November, really, really strong scoliosis demand, saw elective demand across the board in those periods. We had a really solid December, but it was a slowing rate of demand for scoli. And then that kind of continued here into the early part of the first quarter. So, I think what we've seen from a demand standpoint is pretty consistent with what I have been reading, at least from some of the other companies on the scoliosis side or on the spine side in elective. I think what we're really pleased about is the numbers that – we have 23 new users that we captured in 2020. And again, there's only 300 children's hospitals and only a certain number of pediatric orthopedic surgeons that regularly do scoliosis. So, that 23 new users was a very substantial and concrete representation of share gain for us. And we have kind of a goal of that order of magnitude again for this year, and feel like we're off to a really, really good start. So, I think that's what's durable. There's no question we're getting a larger percentage of the take of some of our accounts already. So, some of the accounts that we had before these 23 new users, I think we're getting deeper penetration. But adding new users that are consistently calling for the RESPONSE scoli system, I think, is a very concrete – the thing we're resting on for growth next year. Obviously, we're extremely excited about ApiFix. And we continue to see accelerated interest in being a part of the IRB sites, although, as you know, we have our 20 and will remain there until we fill this 200 patient registry. What I will say, though, is that we can very clearly – we're very clearly deriving revenue and newer customers from our acquisition of ApiFix and people being connected to this non-fusion technology. Not every patient, as you well know, is a candidate for non-fusion surgery. And so, a number of patients are being driven to these clinics that have access to this site. And ultimately, in some of those sites, there are places where we didn't have previous fusion business. And we're definitely seeing an increase in fusion business with our RESPONSE system at locations where that have access to the ApiFix technology. So, like the synergies there. And as that continues to expand and become a bigger part of our business in 2021, 2022, we would expect to see that synergies only get better.