This is one of those kits that every homeowner or DIYer should have in their toolbox. It's a massive assortment of 256 flat washers, split evenly between black rubber and translucent silicone. You get 7 different sizes, ranging from small (11mm outer diameter) up to large (46mm OD), with thicknesses of 2mm or 3mm. The sizes are clearly listed in both metric and inches. These flat washers (also called O-rings or gaskets) are essential for stopping leaks in all sorts of plumbing connections. You'll use them for fixing leaky shower heads, garden hose connections, faucet aerators, washing machine hoses, under-sink fittings, and more. The rubber ones are tough and resistant, while the silicone ones are great for higher heat and have excellent sealing properties. They come neatly organized in a compartmentalized plastic box, so you can easily find the size you need. Instead of running to the hardware store every time you have a drip, you'll probably have the right washer right here. It's an incredibly practical and money-saving kit for basic plumbing maintenance. A total must-have for anyone who likes to fix things themselves.