Three-in-one assault jacket is also known as 2-piece assault jacket, you can remove the jacket single wear and liner single wear, and can be combined together to wear, so it is known as three-in-one assault jacket. 2in1 assault jacket is an assault jacket inside with a fleece jacket, just have a zipper to the assault jacket and fleece connected together, the difference is only the liner can not be single wear, comparatively speaking, the three-in-one function is more comprehensive, can one to cope with a variety of environment, the price is also more expensive. FTM6211 does not have this model, it should be JK99-FTM621, the answer is complete.