I bought it for a trip to Europe to wear under my shirt and keep a credit card or keys. It didn't end up being necessary. I never needed to use it. That doesn't mean it isn't useful in other circumstances--maybe if you're traveling alone and also tend to put yourself in more dangerous environments like crowded clubs or like to walk around without a bag. The big sticker on it leaves a huge sticky residue that won't come off. The color options could be a bit more updated.I'm a world traveler and was looking for a way to hide my main money stash when I'm staying in places where my room isn't secure. This is pretty good. Just don't confuse this for a wallet replacement. Here's why:1. If you keep this on your bra (side or front), you will not have access to it all day long every time you need to get to your money. Picture yourself reaching up your shirt in a marketplace. I suppose it's easier to pull out if it's on your hip, but see #2:2. The design of this thing is such that there's a little flap over the top, like an attached lid. There's also a Velcro strip for going around your bra strap/panties/whatever, and when that's in use it actually covers and locks the lid closed. So, while it's attached to your body, you cannot just slide a credit card or money out of it-- it's locked shut by the Velcro. That's great for security, but it means you're not just reaching under your clothes and sliding out a card to pay for something. You have to remove the whole thing. So, it's not descreet enough to be getting into and out of it all day.HOWEVER, 4 stars because it's a great product if what you want it for is a place to keep your backup money that you don't need that day. This is a long term storage place for your money that you don't need today but didn't feel comfortable leaving in your room/dorm.Comfort: I put a couple of credit cards in it and wore it around the house for a day on the side band of my bra, and forgot it was there pretty quickly, as it's very soft. I also put it on the hip of my bikini underwear for a while, but I didn't like that quite as much, as when I went to the bathroom I didn't like being worried that it would come off. Less movement on the bra. I didn't try the front of my bra, as that seemed silly and the other way worked perfectly.Update: I've been abroad with this for a week now. Lost 1 star for 2 reasons:1. The Velcro sometimes scratches your arm or body-- ouch! I now wear this upside down and the problem was solved. (Nothing falls it because the strap covers the lid.)2. This is made of soft material, and as such it doesn't have much structure. Because of this, and because you have to fold bills in quarters to fit in there, it's a little bulgy. I wear my clothes loosely so I don't notice it, plus you can put it on the inside of your side bra strap to help hold it closer to your body, but there's a limit to how much cash you would fold in there before noticing a bulge. If you wear tight fitting clothes you're best off using this for credit cards since they stay flat, and no more than 1 bill.This item and a sling bag was my way to prevent pickpocketing.. i kept some money in my sling bag and most of the money and Credit cards on this pocket, it was so easy to wear on my bra or panties. Seamless and the material is soft so you. Don't u even feel it. I recommend itThis design is limiting for many bra styles and sizes and would not work with sport bras. Strap area is too short. I have used products successfully in the past that can secure to bra straps. :(Bought this for my trip to Brazil. Best idea ever! Those stupid travelers belts that go around your waist are super uncomfortable, especially in 105 degree heat. The bra wallet is much more comfortable, and while you can't fit your passport in it, you really don't need to have your passports with you all the time. Plus it's a bit more subtle to quickly flip it out of your boobs than to have to lift up your whole shirt with a belt. Another advantage of the bra wallet over the waist belt is that you can wear under everything! (some low cut tops are problematic) But dresses are no problem. I imagine turtlenecks might pose a problem... but who wears turtlenecks anyways?Downsides include, occasionally people can see it, especially if you're wearing something tight or low cut, or bend over. And when you have to get your money out, it can be awkward, or when you have to strap it back in. The plus of this, is that even if people can tell where your money is, they probably won't be able to steal it.Also, if you have too much stuff in it, (cards/change/ect) the bulge can be quite noticeable.Additionally, if you have small breasts, this might not be the product for you. I don't know, if you only kept cash in it, it would probably be fine. It's pretty thin just by itself.Overall, I recommend! Well priced, and very very handy.I have owned one of these for years. They are great for the essential items when going clubbing or traveling or just when you don't want to carry a purse but still need a place to put your ID, cards and cash.It isn't a huge pocket so be prepared to limit yourself to your ID, one or two credit cards and a tiny amount of folded cash. Depending on the shirt you wear, this CAN be accessible without flashing everyone. Be sure to wear a V-neck or looser top so you can reach down into your shirt to access this. If you have to reach up, expect it to be awkward.I have never attached it to my underwear before because I normally wear this with a dress and I definitely don't want to lift my dress to gain access.Since I was already familiar with this item, I bought this for my sister as part of a "travel safety" kit I made for her before she went on a month long backpacking excursion through Europe.I have used similar items throughout my travels and feel it is always good to have extra measures of security to prevent problems rather than trying to fix a problem after the fact.She used it for a photocopy of her passport and a spare credit card and some cash. She said it was way better than trying to keep those items in her pockets or tout around a hideous and touristy money belt.If you have a wide banded bra, then this isn’t for you. I could barely get the fastener around my bra and when I could it was hard to undo.Amazing product. We went to Europe, I kept all my money and credit card safe. I will totally recomended.Great idea