Husqvarna Oiler X-Ring & O-Ring Combo Pack For 181, 281, 288. These are all Buna-N products and are very high quality. I personally have used these on my saws for years with great success.

Part numbers included in this sale x-ring - 501288501 o-ring - 740422400   

Quantity is 1 x-ring and 2 o-rings.

I also have these combo packs for the 61 66 266 268 272. They include an x-ring, see my other listings.