The MMD Vivian Switch is completely different from the MMD Princess Switch. Firstly, the stem material of the Vivian is now modified UPE. We all know that UPE creates a thocky and deep sound profile because of its softness, but softness means it can be easily broken. The modified and strengthened UPE stem solves this problem while still retaining the sound and smoothness of UPE. The top housing of the Vivian switch is our old friend PA12, but the bottom housing is made of something called modified PUM which I truly have never heard of before. The PUM bottom housing creates a deep clacky sound according to a few tests on these switches.
