Q. I am ordering Tefillin straps. Unfortunately, the quality of straps today are poorer than when I became BarMitzvah. The straps do not absorb paint as well and therefore the tefillin paint comes off faster. Therefore, they have invented a new Zach where the leather itself is dyed black and the straps are black on both sides. Therefore, even if paint comes off the straps are still black. Additionally, since the paint comes off the new straps easily, of ten the BarMitzvah boys repaint their own straps and often the BarMitzvah boy is not a Gadol yet Midoraisa. Therefore, the black on both sides straps are advantageous.
However, we have heard that HaRav Miller is not happy with the new straps. Is he unhappy because it is a new thing, and traditionally we Jews need to be wary of new things, in order to survive in Galus without a Sanhedrin. Or is there something halachically to be careful of for which he discourages using these new-style straps? Or is it merely a baseless rumour and we can order the new-style straps without qualms?

A. Rambam’s opinion (H. Tefilin 3: 14, Or Zarua and Arizal in Sha’ar Hakavonos) is that the back side of the retzuos should be preferable black as well, as an aesthetic manifestation. While this is not the accepted Halacha (Mishna Berura 33: 3) there have always been individuals who have worn such retzuos. Rav Mordechai Friedlander Shlit’a, a renowned posek in STaM, member of the Edah Charedis and who was very close with Rav Elyashiv Zt”l, said that the Rav Zt”l, who himself didn’t wear these retzuos, had no issue with those wanting to use them for the preventive advantage they provide. As when with age the top side cracks or the paint peels off, as well as when they turn upside down, especially on the kesher area.
Horav Shlomo Miller’s Shlit”a opinion is that black on both sides retzuos are indeed better, when there are no other questionable impairments involved. (The Rov himself has recently acquired such retzuos.)

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a