The form is identical to the ordinary Super Saiyan 2 form, however when powering up into it the user possesses more sparks in their aura and their hair becomes even more spiked.
Usage and power
In the Dragon Ball Super manga it is revealed that like how the original Super Saiyan form could be upgraded through training to gain power enhancements or become mastered, the Super Saiyan 2 form can be improved as well. By training yourself to death with the Super Saiyan 2 form, you gain the ability to power up into this enhanced state. The strengthened Super Saiyan 2 form is far more powerful than the Super Saiyan 2 state, as it increases the user's power as much as a Super Saiyan 3 (around four times greater than the regular Super Saiyan 2). In the anime this state does not give any extra power to the Super Saiyan 2 form, but is instead simply Future Trunks going up to his max power - making him stronger than Super Saiyan 2 Goku, but still no match for Super Saiyan 3 Goku. Eventually, after training with Vegeta, he became stronger in this form, able to hold his own against Goku Black as a Super Saiyan Rosé and Future Zamasu long enough for Goku and Vegeta to travel back to the present.
In the manga, Future Trunks managed to obtain this form through intense training after realizing that Super Saiyan 2 was not his limit. Future Trunks reveals this form to Goku during their sparring match when Goku transforms into a Super Saiyan 3 to impress Future Trunks - to which Future Trunks responds by taking on this state, prompting Vegeta to note with surprise that Future Trunks' strength was a match for Super Saiyan 3 Goku's, and requiring Goku to become a Super Saiyan God to take down Future Trunks. Future Trunks uses this form once again in the manga, able to take on Super Saiyan Rosé Goku Black and take down Future Zamasu. However, once Goku and Vegeta travel back to the present, Future Trunks is beaten down easily in this form by Black. In the anime Future Trunks states he will use his Super Saiyan 2 form's max power upon seeing Super Saiyan 3 Goku, however he is easily taken down by Super Saiyan 3 Goku, who defeats him with one blow.