Is there a sleeve for full size mags when used in a compact?

You mean X Grip?
X-Grip Mag Adapter S&W M&P 9mm Luger 357 Sig 40 S&W Full Size Mag to

THANK YOU!

I have a full-size 17-round magazine with the XGrip that I use in my M&P 9c when I take it to the range. It is extremely comfortable and reduces the number of times I reload. I don't use it for EDC because it makes the pistol "off-balance" in the holster and also, harder to conceal. However, it is great for home defense magazine or back-up. I recommend this combination.