New construction frame-in with collar for pre-wiring and easier layout planning.. . Compatible Fixtures:. NIOC-2RNB: 2" Iolite Can-less Round Bullnose. NIOC-2RNDC: 2" Iolite Can-less Round Downlight. NIOC-2RPH: 2" Iolite Can-less Round Pinhole. NIOC-2SNDSQ: 2" Iolite Can-less Square Downlight