Hey all. I hope this exact topic hasn't already been covered, but I couldn't find it on TB. I got a set of D'Addario ECB81S flatwound short scale XL Chromes from JustStrings thinking I would swap strings on my wife's 6 year old Fender Mustang for her. But low and behold and much to my surprise - they are way too short! Of course I had to open the package to get out a string and (of course) JustStrings won't take them back. Here is how D'Addario replied to me in an email - and I quote: "You can't always tell which strings you need just by the scale length of your bass. Some basses are strung through the body, and the distances from the bridge to where the ball-end locks in, and the distance from the nut to the tuning pegs are not always exact. The best way to figure out the scale length would be to perform the following test: 1) Mark the lowest pitched string (while on your bass) at the nut with a marker. 2) Remove the string 3) Measure the distance from the inner edge of the ball end the mark you just made. 4) Record this length and refer to the following chart. Length String Set Scale Up to 32' D'Addario Short 32" - 34" D'Addario Medium 34" - 36" D'Addario Long 36" - 38" D'Addario Super Long I hope this helps you." .... and by the way the "mediums" you need are on backorder. Nowhere on any "string" site is this "string-through-body" problem mentioned. Now I'm out $28.91 because I opened the package. I hope this post helps someone else avoid this expensive (to me) hassle.