The NiSi 15mm f/4 Sunstar ASPH was announced last year in Black and later in Silver, but the Silver edition has only begun to show up at places like B&H Photo and it looks like NiSi has been selling it directly through Amazon in low volume. It even looks like they might have had plans for a White copy of this lens as can be seen below in Kai’s video review, but at this point, I wouldn’t be surprised if it has been canceled due to supply chain constraints.
Silver NiSi 15mm f/4 Sunstar ASPH: Amazon / B&H Photo
Black NiSi 15mm f/4 Sunstar ASPH: Amazon / B&H Photo