it means u can use your internet free of cost for 10 hours(cumulative over a period of one month) during day hrs which i think are frm 630am to 1030pm And 50 hours(again for one month) during the night hours, which wud be 1030pm to 630am.P.S: The timings i specified above are the official day and night timings for the home699 and home999 plans in delhi, i can't confirm whether they r the same for ur plan too or not.