text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_name_66 (specific_impulse__s_ INTEGER, sfc_in_lb__lbf·h_ VARCHAR, effective_exhaust_velocity__m_s_ VARCHAR)
  ### Question:
  what is the average specific impulse for engines that have a SFC in lb/(lbf·h) of 7.95, and a Effective exhaust velocity (m/s) larger than 4,423
  ### Answer:
  SELECT AVG(specific_impulse__s_) FROM table_name_66 WHERE sfc_in_lb__lbf·h_ = 7.95 AND effective_exhaust_velocity__m_s_ > 4 OFFSET 423