Sold by Classic Light Bulb, an authorized distributor of Ironsmith Lighting Products.
These plastic spikes are made from high quality ABS plastic. ABS plastic is known for its durability and resistance to corrosion from the elements. Making it a top choice for a part which will be submerged in dirt, grass and moisture for the rest of its life.
In-Ground stake with 1/2" NPT thread and Side Wire Way for Easy Installation.

Measurements 8.2" Long x 3.3" Width x 3.3" Height.

Works with most big brand name fixtures. Just check the thread.