Rear spacers.. Does anyone know if these are quality?

My friend has a them on the front of his 250r. .they r strong and have held up good for a couple years but they are weigh alot and made the front heavy

Thanks for the info, they are the cheapest ones on eBay and i would put them on the rear. Im deciding whether to go with extended rear hubs or these rear spacers.
 
I would recommend getting yfz450r rear hubs...only the R model rear hubs add width...I think an inch or inch and a half each side