What is the measurement of the small and medium size??? like length of arms and chest etc dimensions trying to figure out what size I am..... also, i plan on thru hiking the Appalachian Trail and this looks likea good combo for rain/cold weather is this a good choice for teh AT?

Tech Specs:

Material:

[shell] Marmot MemBrain with DWR 

Insulation:

[removable liner] MarmaLoft, DWR finish 

Fabric Waterproof Rating:

water-resistant 

Venting:

pitzips 

Pockets:

2 front, 1 interior 

Seams:

fully taped 

Powder Skirt:

no 

Hood:

yes, removable 

Liner-Compatible:

yes, removable liner included 

Recommended Use:

backpacking, hiking, snowsports 

Manufacturer Warranty:

lifetime