Valmiki Ramayana Yuddha Kanda Sarga 76 Shloka 39

सशरम् those arrows, उत्तमम् best, तस्य his, तत् that, धनुः bow, विद्युदैरावतार्चिष्मत् shining like the cloud with flashes of lightning, द्वितीयेन्द्रधनुः second bow of Indra यथा like that, भूयः shone, शुशुभे released.

Those best arrows fixed to the bow were shining like the cloud with flashes of lightning, and like a second bow of Indra.