Surah Ar-Rahman 55:66

فِيهِمَا عَيْنَانِ نَضَّاخَتَانِ

In both of them are two springs, spouting.

Translation: Saheeh International

Tafsir

In both of them will be two gushing fountains rushing with water unceasing.

Excerpt from Tafsir al-Jalalayn, commentary on 55:66, via Quran.com. The reader has the full commentary and 9 more tafsirs.