One of the best cosmetics purchases I've ever made, I'd thoroughly recommend it even to people on a budget. I know, I know, it seems expensive for what it is and how much is in the bottle - £10 for 9ml excluding P&P - but hear me out. It's a silicone based product that acts as a waterproof sealant with whatever you use it with - once the volatile silicones have dried off it results in extended wear times for make up and is water and sebum resistant. What makes it worth the price is the sheer number of uses it has - used with powder eyeshadows, it can let you use them as eyeliners. For kohl eyeliner pencils, gel liner pencils, and standard liquid liners it also can greatly improve staying power. You can use it to fix brow products and also as a primer on eyelids too. Some people have success using it as an under foundation primer but I've not tried it for that purpose myself.
What it also does - and this is where it really can help you out if money is scarce - is revive cream eyeshadows, cream blushers, and gel eyeliners that have started to dry out in the pot. Half a drop in the product itself, mix in, and suddenly I've got a useable cream eyeshadow again and I don't need to buy a new one. I need to be careful doing so however as too much can result in unwanted changes to the finish and level of pigmentation once on the skin.
It comes in a little square shaped glass bottle and there is a dropper within. The lid has a button you press to withdraw product and also to dispense from the pipette , and lets you press slowly so you can get the amount you need out and not an unwanted torrent of product.
It's the most versatile item in my make-up collection and I wish I'd found it sooner. Can't praise it enough! I love it!