What is the weight of the player with the longest time on ice in the player’s first 7 years of NHL career in kilograms?
weight in kilograms refers to weight_in_kg; longest time on ice in the player's first 7 years of NHL career refers to MAX(sum_7yr_TOI);
SELECT T2.weight_in_kg FROM PlayerInfo AS T1 INNER JOIN weight_info AS T2 ON T1.weight = T2.weight_id WHERE T1.sum_7yr_TOI = ( SELECT MAX(t.sum_7yr_TOI) FROM PlayerInfo t )