I have no idea how long this sale will last, it appears to have popped up some time last night, so my recommendation to you is that if you are in need of some very good in-ear headphones then you should snap these up right away. It might be a one day thing, you guys/gals!
As for why you should grab these while you can, first off Sennheiser makes AMAZING headphones. I can't remember ever having checked out their in-ear ones but I know people who swear by their other products.
Also, these are selling for $24.99! Regularly price is $75+. That's a seriously insane discount. I have some Bluetooth in-ear headphones myself, but I use wired ones at work when at my desk and I've been thinking about picking up a new set for use when I'm out and about and wearing my Bluetooth ones would pose problematic for whatever reason. (The fact that my new sweater has pockets on the inside and cable routing just for wired headphones is kind of a bonus on that front.)
Now it's only fair to warn you that the built-in controls are hit or miss depending on your device. People across various Android related sites have reported that they work perfectly fine on some devices and not at all on others. I suppose you'll have to see for yourself if yours are compatible or not. If you're like me and use Android Wear this is a non-issue though. I'm so used to accepting or rejecting calls and what have you from my wrist that built-in controls on headphones no longer matter to me.
I can wholeheartedly say I've definitely seen worse headphones at that price point and then some. (My mom's not even two week old Beats in-ear headphones have already crapped out. I FUCKING CALLED IT! The first thing I said when she told me was, "Frommer's tried to tell you, but you wouldn't listen." She stared daggers at me. "Shut up! Make them work again." I just laughed and walked off. I'll give it a go over the weekend, but there's a reason I warn everyone against buying Beats headphones. You're paying top dollar for the name, not the hardware and you can get the same sound off ANY other set of headphones if you use an Android device since it's all software that does that. If you're rooted you can flash it with a custom recovery in point of fact.)
Prices will go back to normal, folks. So snag a pair while you can!