This is the ruffwear approach pack. Used only once on a 6 mile hike in Tahoe. I’m not sure how the stains got there (thinking tree sap and dirt but it had been washed thoroughly!) it’s a size small and fits my 40 lb dog perfectly. She just hates it and it’s easier for me to carry all her stuff on backpacking trips anyways. I’ll list the link to the website for sizing information below. Originally cost $110.