It is an option available only on BSE. While placing a market order in BSE, you can define the protection %. Protection % ensures that the actual traded price of the order does not deviate more than the defined % from the best available price when the order hits the market.

For e.g. If you place a Buy order at Market price for 100 shares of Axis Bank (price protection = 10% and the best offer price (BOP) = Rs. 1410 at the time order hits the market), then the order will get executed either at Rs.1410 or between Rs.1410 and a maximum of Rs.1511 (1410+141).