The redesign also gave Dorogusker and company a chance to tweak the feel of the swipe itself, which is a crucial detail that makes the product itself feel trustworthy despite its tininess. By tweaking the design of the spring to which the magnetic read head was attached, the team was able to fine-tune the friction customers feel when swiping their card. At one point in development, they found that the level of contact they needed to successfully transfer data from a card resulted in a swipe that felt too loose. And when the swipe felt too loose, it felt like it wasn’t working, and would thus require another swipe. So they increased the friction above what was actually needed–an adjustment that was overkill from a technical point of view but resulted in a swipe that felt perfect to the hand.