You can screw them together by hand to make your curtain rod as long as you need it to be.
eBay
2.6m Stainless Steel Spray Extension Pipe Sprayer Tool for Garden Green Space
Aliexpress UK
22 Pcs Polystyrene Sphere Balls for Crafting Foaming Texture Painting. - It's used for holding curtain rod, closet rod, shower rod, clothes pole, hanging rod and etc. 2 Pcs Cabinet Handles Brass Knobs for Cabinets Cupboard Door Pull.
eBay
NEEWER DS001 Table Overhead Camera Mount Arm 11.8-20 inches/30-51 cm Telescopic Extension Arm for Table Stand
Aliexpress UK
Spring rod can provide consistent tension for a long-lasting, tight, secure fit, no drilling, screws or any tools. 【Multipurpose】Short shower curtain rod is suitable for all kinds of walls such as wood, glass, tile, wallpaper, etc.
eBay
Professional Tripode 1/4 Screw Handheld stabilizer adapter Adjustable Tripod Monopod Mount Extension Rod For DSLR Camera
Aliexpress UK
【Simple Installation】Our extendable rod is designed for ease, allowing you to stretch and twist without the need for drilling, ensuring a hassle-free set-up that anyone can achieve. Installation is straightforward and tool-free—simply extend, twist, and lock the rod into place.
eBay
Ergonomic Weed Eater Handle Grip - Lawn Trimmer Extension with Bracket Clamp, Comfortable Weeder Handle for String Trimmer
Aliexpress UK
【Modern Curtain Rod】: The simple design of the flat finial is different from the traditional round finial curtain rod, perfect for all kinds of narrow places, and provides a visually unique and modern style.
eBay
Toocki Male to Male Dual USB A Cable USB3.0 High Speed Extension Cable for Radiator Camera 5Gbps Fast Transmission USB Data Cord
Aliexpress UK
Each horizontal rod for hanging curtains can hold weight up to 40 LBS without any sagging. Suitable for any type of curtains such as heavy blackout curtains, light sheer, rod pocket curtains, tab top curtains.
eBay
1PCS Aluminum Alloy 17mm Ball Head Universal Extension Rod Diving Fill Light Arm Butterfly Clip Photography Clip Arm Accessories
Aliexpress UK
Wide uses, can be applied to connect and extend the of curtain holder, wardrobe rod, etc. 2 Pcs Stainless Steel Ring with Handle Baking Cup Cover Milk Tea. Are you looking for a professional and practical clothes rod connector?.
eBay
3/8 Screw connection for ARRI RED SONY Camera car mounted shooting extension bracket
Aliexpress UK
Its user-friendly design allows for effortless operation, reducing the need for ladders or excessive reaching. Travel Compass Marine Compass Outdoor Portable Compass Pocket Camping Compass. 1 x Window Opener Pole.
eBay
SmallRig EOS C50 Cage Kit for Canon EOS C50 Dedicated Handheld Kit XLR Handle Extension Rig with Cable Clamp Arca-Swiss 5657
Aliexpress UK