Normaly when you buy one encoder the reference it's LPI not DPI . In the description there are the lpi and dpi , but the first information it's the dpi and i ordered the item based in this information, i have made a mistake . This comment it's only to avoid mistakes when future buyers make one order The provider on the beginning have made the same mistake too because the first answer i had from him was pay 0.01 $ and i will send the right encoder , i have payed this amount and the day after they inform me about my mistake., that means the description there are in the item can be better I dont need this amount 0.01 $ but will be a good finishing only some words from the provider.