They can be used for flue gas, ventilation ducts, etc. Designed to protect pipes from precipitation, as well as to increase traction.
eBay
5-25pcs Black Silicone Rubber Hole Caps T Type Plug Cover Snap-on Gasket Blanking End Caps Seal Stopper 2.5mm-15mm
Aliexpress UK
The single wall chimney system is a quick and easy way to make a new chimney that is safe, takes up little room and is fast to install. Stainless Steel Single Wall Chimney Accessories. Sheet thickness: 0.5mm.
eBay
1/8 1/4 3/8 1/2 3/4 Male Female Thread Brass Pipe Hex Head End Cap Plug Fitting Quick Connector Brass Universal Faucet Adapter
Aliexpress UK
Disused Chimney - Strap Fix. Anti-Down Draught Bonnet Cowl. Terracotta and Buff. This cowl is great if you want to stop birds from nesting inside/on your chimney. Not only does it do the job you want it to do, it looks stylish too.
eBay
Red Copper Hexagonal Nut/Locking Screw Cap M3M4M5M6M8-M30
Aliexpress UK
LENGTH OF COWL 20 CM. MATERIAL - Steel - coated with black heat proof paint up to 6 00°C. HS, IV 41 to 49, IV 51, 55 & 56. KA 27 & 28, KW 15 to 17. PA 20, PA 41 to 49, PA 60 to 78, PH 42 to 44. Isle of Man (IM), Channel Islands.
eBay
10pcs Square Plastic Black Blanking End Cap Tube Pipe Insert Plug Bung 15x15~60x60mm
Aliexpress UK
Universal fitting, simply squeeze the legs into your existing chimney pot. Designed to fit chimney pots between 8" (200mm) and 10" (250mm).
eBay
Barrow G1/4" Ultra Thin End Cap Fitting TBLDS
Aliexpress UK
Upgraded Durability: Made of stainless steel, our rain cap is designed to keep your chimney debris-free and well-protected from harsh weather. This chimney vent cover cap is designed in the shape of an umbrella and made of high-quality stainless steel material.
eBay
AI0001100R For Roca Dama Giralda Senso & Hall Soft Close Toilet Seat Hinge Metal End Caps Only
Aliexpress UK
This applies to Storm Collars, Brackets/Supports, Locking Bands and Plates. Exceptional Thermal Properties: KW Pro is classified as G50 due to its outstanding thermal efficiency. KW Pro Range Chimney System.
eBay
Bathroom Basin Sink Overflow Ring Six-foot Round Insert Chrome Hole Cover Cap Y98E
Aliexpress UK
For ventilation ducts, chimneys and air extraction hoods. Guards provide maximum protection without compromising chimney performance. 1 x Chimney Cap. Made of high-quality 304 stainless steel, cold and high temperature resistant, durable.
eBay
Durable Ibc Tank Fittings S60X6 Coarse Threaded Cap 60Mm Female Thread To 1/2 ", 3/4", 1 "Adapter Connector
Aliexpress UK