It fits like a glove. I’m a 40” chest and would definitely not want the large. Even if I was bigger the medium would still the correct fit, despite the size guide. I bought it for MTBing and is definitely the best jacket for this purpose.Also excellent service from Dirtbike Express.

Comfortable fit and has full torso, shoulder and arm coverage, moves well and good breathability.

Awesome design.

Pretty snug but great overall. I am 215lb and 6'2 and I got an XL.

Comfortable

The Fox base frame pro D 30 jacket is comfortable cool and offers great protection.

Comfortable period

So much more comfortable than external armor, you'll forget you're wearing it! I use it as my base layer when it's hot out, no need to put an Underarmour shirt on underneath, the mesh base is comfortable and obviously breathes well.Having the pads be removable is a good design, because you'll definitely want to wash it.

Cushin' for the Pushin'

The new Baseframe is so much better than wearing separate pieces of gear. It goes on so easy and fast and I forget it is there when I am riding. The shoulder protection was the most important for me and this nicely covers your AC joint and all the boney portions of your shoulder. I am 5'9" 175lbs, medium fits great, could be a little looser around the chest strap but I workout a lot. No uncomfortable spots though. Highly recommend, no more tight and sliding elbow pads.

D3O

Seems like it should be worn as your first layer, maybe with a form-fitting (almost compression) tee shirt underneath.Loses a star because of the straps around the back & chest protectors. I'm running without them, the fit is tight enough and the straps complicate getting in and out of this thing.The removable section in the back protector for a neck brace isn't enough for the Leatt 4.5, and the stand-offs on the front of that collar land on the chest protector. I'll run a different collar and keep the full D30 for the back and chest.I couldn't find sizing information on the Fox site (there's a link on their page, but the result doesn't render) nor here but for one example in the video. So I'm including a photo from the hanger; I found the chart to be accurate.

Great item

Fast postage and a great item. Very happy with this purchase.

Well worth the money.

I really like this under jacket, you can wear it as the base layer, and I've worn it over a long sleeve when it was a bit colder out, I feel protection is really nice. I have a few couple good falls and I feel like it has done its job very well.

Works great so far

I purchased this to protect myself while snowboarding. I've used it a handful of times and works great. I am typically an XL and purchased a L, fits fine.