Warning sphere is manufactured with bright colors, so it can warn aircraft pilots in daytime and nighttime. It is made from FRP (fiberglass reinforced polyester) and it is designed of two halves clamping together, making it have solid structure. So it will not swing even though strong wind. Besides, this type of warning sphere is designed of groove on the side, which can prevent distortion, deformation and rainwater penetration. Therefore, the drainage hole is unnecessary.
Specification:

Sphere body material: FRP (fiberglass reinforced polyester).
Visible distance: 1250 m from the air and 350 m from the ground.
Voltage range: 35 kV - 1000 kV.
Color: single color (aviation red, aviation orange, aviation white), two colors (white/orange, white/red).
Ambient temperature: -40 °C to +90 °C.
Conductor diameter: 6.5 mm - 55 mm.
Sphere diameter: 600 mm, 800 mm, 1300 mm, also can be customized.
Weight: 6.9 kg, 9.0 kg, 15 kg.
Thickness: 3 mm.
Warranty: 2 years.
HS custom code: 39269090.
Standard:

ICAO Annex 14, 6th Edition, July 2013. Annex 14 to the Convention on International Civil Aviation.
FAA AC 70/7460-1L, obstruction Marking and Lighting.
Date Issued: December 04, 2015.
Responsible Office: AJV-1, Airspace Service
Description: This Advisory Circular (AC) sets forth standards for marking and lighting obstructions that have been deemed to be a hazard to navigable airspace.
Advantages of warning sphere:

Unique groove design on the side, preventing distortion, deformation and rainwater penetration.
Resistant to weather, high temperature, water and dust.
Excellent UV, ozone, sunlight and attack resistance.
Stable color, not fade, recyclable.
Two halves clamped together design, not swing even though strong wind.
Light but durable, solid structure.
Maintenance free.
Does not slip, no oscillate and chafe.
Designed of preformed armor rods, protecting conductor.
Fast and easy installation.
Two halves orange warning spheres are on the ground.
Warning sphere is designed of unique groove on the side, which can prevent distortion, deformation and rainwater penetration.