From the manufacturer's official website:

THE FI.MILLE_S5 IS TAILORED FOR TOTAL COMFORT DURING LONGER RIDES. FULL ERGONOMIC PATTERN DESIGN; PROVIDING MUSCLE-COMPRESSION TOGETHER WITH TOTAL MOVEMENT FREEDOM THANKS TO ITS 4-PANEL CONSTRUCTION. IDEALLY SUITED FOR MORE ROBUST RIDERS WHO PREFER A “LESS TIGHT” FEELING

THE S5 DIFFERENCE:

Engineered for high-performance cycling. Made for a cycling body that cycles for fitness, training or racing. ASSOS cycling shorts are not apparel, but equipment which enables you to free your mind, go further, longer and faster.
HOW? Every single aspect of product creation was engineered with one clear objective: provide Total Comfort when in the saddle. Unleash your personal potential because, with ASSOS, your physical capacities are not limited by the equipment, but solely by your mind. Focus on the essence: your pleasure! In return for this, there is a “price” we all have to pay: don’t expect your S5 shorts to last forever. They were not created with longevity as main objective. We nevertheless managed to make them more durable* than the previous FI. generation. Your satisfaction is our objective! DO NOT use ASSOS cycling shorts for leisure activities such as walking the dog or getting the croissants in the morning on your leisure bike. That would simply be a waste, an overkill and in conflict with the product's DNA.
* might differ depending on how you treat them, please consult owner’s manual for proper handling

CONSTRUCTION:

• NEW ASSOS TYPE A.430 COMPRESSION FABRIC
• NEW REFINED ASSOS AEPD PATTERN DESIGN
• NEW NEXT-TO-SKIN FABRIC COMPOUND
• NEW INSERT SHAPES NEW ELASTIC LEG GRIPPERS

IMPROVEMENTS:

In comparison to the previous ASSOS FI. generation, the improvements can be summarized as follows*:

• -25% LESS VOLUME_LESS WEIGHT
• -23% LESS PRESSURE ON GENITAL AREA
• +35% EXTRA BREATHABLE FABRIC / INSERT / AEPD
• +18% MORE COMPRESSION ON MUSCLE ZONE

*The above results are an average, indicative, figure. Comparison tests were conducted at the ASSOS Textile Lab confronting the outgoing version of the FI.Uno, FI.Mille, FI.13 with their s5 successors. The data obtained is the result of various comparison methods. A combined testing process of single fabrics, pattern designs and assembly techniques was applied.

EXPERIENCE:

ASSOS CYCLING SHORTS ARE CREATED WITH AN ORGANIC APPROACH: DESIGNED TO “MERGE” WITH YOUR BODY WHEN ON THE BIKE.
DECIDE TO GO FOR A RIDE_
CHOOSE THE CLIMA RANGE_
CHOOSE YOUR COMFORT_
GET DRESSED_
GET IN POSITION_
GET BODY TEMPERATURE & HEARTBEAT SLOWLY UP TO SPEED_
ENJOY THE RIDE
AND HOURS LATER REALIZE THAT “ONE WAS ACTUALLY WEARING SHORTS“!

For more information, please visit this product's webpage.