Bodo Knudsenwrote a review of Castelli RoS Shoe Cover on October 28, 2018
Familiarity: I've used it once or twice and have initial impressions
Castelli has been marketing the RoS (Rain or Shine) slogan and line of cycling clothing/accessories this year. There are some new products and some carry overs from prior seasons. I've been putting together a new kit that can handle some light rain in case I get caught on some longer road rides. As part of this I ordered the RoS shoe cover.
The covers arrived last week. They have a rubbery outer material that runs over the top of the foot and on the outside of the upper portion. The material on the inside of the foot and leg is not rubbery but not quite neoprene either. The inner portion has a light fleece backing. The cuff is longer than most shoe covers and fits nice and snug with the goal of keeping rain out. The zip is long and taped to provide an effective seal against water. There are some reflective elements built in too. Overall the design does look quite premium.
I have only used them once so far. The temps were between 40 and 45 degrees, a little light drizzle but not heavy rain, some road spray and some wind. I wore the size L RoS covers over a pair of 42.5 Sidi Wire SP Carbon Push shoes wearing Gore Thermo road socks. The covers fit perfectly over the shoes and wear quite easy to pull on. The closed up well over my Rapha tights and caused no issues while pedaling. Initially I thought my toes were going to get cold but as I road they were perfectly fine.
I do think that in colder temps closer to 32, they might not be warm enough with the shoe/sock combo I used today. A heavier merino sock may help here. If it's colder but dry, probably one of the heavier neoprene options might be the way to go.
It's interesting to see the pieces that Castelli has put together for the RoS line as they do span different conditions. For example I also bought the Spetacolo RoS glove (https://www.competitivecyclist.com/castelli-spettacolo-ros-glove?s=a) and it is fairly heavily insulated and I didn't wear it on the same ride as I thought it would be too warm. For this ride I wore a pair of Gore Windstopper gloves that are lightly insulated and regulate extremely well.
Although I have only tried these on one ride, I do think this is a quality product and would compliment a kit geared towards damp or wet riding. They would likely pair extremely well with Rapha's Shadow line or Castelli's Gabba line. They also would work well with some of the pieces in the RoS line. However if you are looking for something more insulating on colder days, there may be better options.