Just a quick note in case I left a misunderstanding about changing tubes in the T4 - Yes, unless you use a tall tube like the 6289 or 6414, you will need to remove the lid to change tubes. That means 8 Philips head screws need to be un-screwed. They are very, very short, so it's not like you are twisting your wrist for several minutes. However, the spudger tool is needed to simply lift the lid. Doug tries for almost seamless casework in his designs. (He often succeeds!) So the lid can sometimes be wedged a bit. By no means, however, is it like the casework on an iPod/iPhone/Android. The spudger is not needed to push into a seam. It's simply that once the screws are unscrewed, there's nothing to grab onto to lift the lid. It can be slightly wedged sometimes, but if the tubes weren't there, use of a finger in the tube holes is all that's needed to pop the lid up enough to grab it on the edges and lift it away. Unfortunately, there's very little chance the tubes aren't going to be there. The spudger is thin enough to slide in-between the side of the tube and edge of the tube hole. You position the end of the spudger under the case lid at that point and lift. Then your fingers can grab the edges of the lid and move it out of the way. (The spudger is not balanced enough to lift the lid entirely without dropping it.) I used a dental pick to pop the lid for a long time on the prototype, but that was because I wasn't so concerned about scratches around the tube holes. The spudger won't scratch. If I could've found a plastic hook that wouldn't easily bend, I would be using that and including one with the amp. The spudger won't bend and is the best thing I've found. It's also a useful tool for other things not T4-related.