Perhaps a 6mm and a 2x barlow lens. If it comes with a barlow lens Perhaps get a 10mm Or get a 2 inch eyepiece.
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https://www.amazon.com/Meade-Instruments-2-Inch-Waterproof-Eyepiece/dp/B005LHMLIQ/ref=sr_1_4?keywords=2+in+eyepiece+telescope&qid=1561694586&s=gateway&sr=8-4I got this one last xmas and have used it quite a bit. I don't have a whole bunch of eyepieces so i'm not a huge expert. But this eyepiece seems to have a good specs for the price.
https://www.amazon.com/Orion-8920-Expanse-Telescope-Eyepiece/dp/B0000XMXXO/ref=sr_1_2?keywords=orion+6mm&qid=1561694668&s=gateway&sr=8-2
This is the first yeepiece I bought and I haven't upgraded past it yet, i recommend.
If you don't want to spend that much then Buy the gold line pieces, called svbony on amazon. Decent pieces for being incredible cheap.