The art of not caring.
Given the added abuse and hardship of off-road riding, we wouldn't necessarily assume that a road saddle could easily transition from tarmac to trail. Selle Italia doesn't care. The only difference between the SLR X-Cross Flow Saddle and its road counterpart is the addition of a high-grip finish at the ischial support areas for grabbing baggies. While this adds 5g of claimed weight, it also means you're that much more planted on the saddle while muscling the bike through rock gardens and root-latticed switchbacks.
The SLR X-Cross Flow has the same carbon-infused shell as the road model, which combines with the Ti 316 alloy rails to provide a touch of engineered flex for comfort that doesn't feel like a bounce castle. It also features the same extra padding — arguably more welcome here than on the road version — and is wrapped in the same durable, wipe-to-clean Fibra-Tek material. The SLR X-Cross' titular Flow cutout is a little bit smaller, but that also makes for a larger support platform for translating body english on tricky lines.