Horrizon Hobby has the specs on the JR 4031 servos. I still have several that came with a JR pattern radio (PCM 9)I purchased new several years ago. I still use the servos in sport models. I don't have the exact specs as they are not printed in the owner's manuel. Coreless, around 55 oz torq I believe. Great servos, mine have been trouble free after hundreds of flights.