<Table> <Tr> <Th_colspan="2"> Sky Sports Box Office </Th> </Tr> <Tr> <Th> Launched </Th> <Td> 16 March 1996 </Td> </Tr> <Tr> <Th> Closed </Th> <Td> 4 January 2017 (2017 - 01 - 04) (Cinema) </Td> </Tr> <Tr> <Th> Owned by </Th> <Td> Sky plc </Td> </Tr> <Tr> <Th> Picture format </Th> <Td> 576i (16: 9 SDTV) 1080i (HDTV) </Td> </Tr> <Tr> <Th> Audience share </Th> <Td> ~ 0.00% (September 2017 (2017 - 09), BARB) </Td> </Tr> <Tr> <Th> Country </Th> <Td> United Kingdom </Td> </Tr> <Tr> <Th> Broadcast area </Th> <Td> United Kingdom Ireland </Td> </Tr> <Tr> <Th> Formerly called </Th> <Td> Sky Box Office (1996--2011) </Td> </Tr> <Tr> <Th> Sister channel (s) </Th> <Td> Challenge, Pick, Real Lives, Sky One, Sky Two, Sky Arts, Sky Atlantic, Sky Cinema, Sky Living, Sky News, Sky Sports, Sky Sports F1, Sky Sports News </Td> </Tr> <Tr> <Th_colspan="2"> Availability </Th> </Tr> <Tr> <Th_colspan="2"> Satellite </Th> </Tr> <Tr> <Th> Sky </Th> <Td> Channel 491 (Sports) Channel 492 (Sports HD) </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Sky Sports Box Office </Th> </Tr>

What number channel is sky sports box office
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