I bought some cheap ones from Amazon. I couldn’t see behind me but the ones I bought helped out a lot. You need to put a little bit of locktite, I kept having issues where the wind blew it loose.

NICECNC Black Universal 10mm Stem Mirror Mount Risers Extenders Adapters for Motorcycle,Dual Sport,Cruisers,Scooters,Sportbikes(2PCS Right-Hand Threaded) https://smile.amazon.com/dp/B075TFPPQ4/ref=cm_sw_r_cp_api_glt_fabc_V3DW9RR18ZRYCM2DR1VC?_encoding=UTF8&psc=1

Take a look at these as well. I am using them on my Monkey, and both my boys have them on their Groms. They don't really increase the overall width of the bike like bar ends do, which can be a blessing if you have a tight garage or lane filter.

https://www.amazon.com/NICECNC-Universal-Motorcycle-Sportbikes-Right-Hand/dp/B075TFPPQ4/ref=sr_1_7?crid=3PT9E4E64HTWN&keywords=mirror+extenders&qid=1647981838&sprefix=mirror+extenders%2Caps%2C92&sr=8-7

Edit: otherwise just be really careful and remember that the painted white lines on the road are very slippery when raining. One of my sons had his frst crash when the rear tire slid out on a stop bar in the rain. He was fine, and the bright side is that it only costs about $150 in new and used parts to fix the bike.

I’ve used these on all of mine. They work good and the stock mirrors are pretty decent quality

https://smile.amazon.com/gp/product/B075TFPPQ4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1