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Selle Italia SLR Boost Endurance Superflow L3

The SLR Boost offers a generous cutout, supple padding for endurance riders, and added width to accommodate wider sit bones.

Review Rating


A carbon beauty with just enough padding and fits like a tailored suit.


Super light, especially given its comfort level



Our Thoughts

If price is no object and you want an anatomic saddle that feels exquisitely comfortable, the SLR Boost Endurance Superflow checks all the boxes. While other long-distance or comfort-focused saddles weigh twice as much as you’d like, this svelte performer is surprisingly lightweight.  

Size Reviewed

248 x 145mm




Selle Italia

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The SLR Boost Endurance Superflow is an endurance-focused version of the standard SLR Boost Superflow, featuring more width and padding. Don’t get it confused with a beach cruiser saddle, however, as it’s still a very svelte and lean performer at just over 200 grams.


It’s relatively short at 248mm, yet somehow felt like it afforded a good amount of fore-aft body movement – likely due to its inward curvature and narrow nose. The SLR Boost’s width registers at 145mm, though our measurements put this closer to 150mm. A narrower S3 option is available, at 130mm width.

Selle Italia calls its saddle padding Light Gel Plus, and positions it as a thicker, more robust padding for long-distance riding. In the flesh, however, it appears to be thin and minimal – suggesting that this might be a rough-riding racing perch. 

The ‘a-ha’ moment comes when you actually start pedaling on the SLR Boost; we found that it brilliantly executes its comfort goals. The rear section is expertly tailored for sit bone comfort, with a combination of side-to-side curvature and a subtle forward slope. The edges of the saddle are gently positioned to fall away from your sit bones – eliminating pressure and encouraging (but not forcing) forward hip rotation.

SLR Boost saddle

The padding, though it appears thin, felt like the perfect amount. The SLR Boost Endurance Superflow is a hidden gem among ergonomic saddles. One tester said, “ I often prefer soft-ish saddles and thought that the SLR would be too firm and uncomfortable, yet it managed to become one of my favorites – and the one that I most easily forgot about while riding.”

Selle Italia offers a ton of options, and perhaps that’s our only criticism – that gems like the SLR Boost Endurance Superflow may become lost in the shuffle. It punches well above its weight in terms of comfort, but that technology comes at a hefty dent to your wallet. We consider this our go-to saddle for weight-conscious consumers that want a wide cutout and maximum comfort, price-be-damned.