From the manufacturer

The world's best-selling, most trusted cam just got better. 

This extendable C4 contains all the features of the latest C4, with the added versatility of an extendable sling. Perfect for wandering routes that weave around corners and roofs, the extendable C4 helps dial in your ideal rope line without the added weight of extra runners. With the same lightweight and optimized lobes as the traditional C4 and a comparable overall weight, the C4 extendables work well in conjunction with a set of C4s or as a full rack on their own.

Features

• Same lightweight design as updated C4
• Double-axle design offers the widest range for each cam unit
• C-Loop continuous cable stem design is strong and durable
• Extendable sling

Specifications

• Weight: 107g | 123g | 140g | 180g
• Size Range: .75 - 3
• Materials: 40% Aluminum, 30% Steel, 5% Nylon, 5% Dyneema, 10% ST801, 5% Grilamid, 5% Polyurethane