Table schema:
CREATE TABLE table_16439764_1 (time_to_ft__m__at_25°__seconds_ VARCHAR, shell__lb_ VARCHAR, max_height__ft_ VARCHAR)

Question: Where the height range is higher than 20000.0 and the shell weight is 12.5, what is the time to feet ratio at 25 degrees?
SQL: SELECT time_to_ft__m__at_25°__seconds_ FROM table_16439764_1 WHERE shell__lb_ = "12.5" AND max_height__ft_ > 20000.0