I found this deal when I was looking for an SD Card for my Canon R6. It is the cheapest I have seen
CamelCamelCamel.
Yup, BIG difference. Extreme Pro is UHS-II (well, newer or current ones anyway), Extreme is UHS-I.
This UHS-I card is nowhere close to 180Mb/s on Write speed - this is the Read speed. It will only write at around 90-95Mb/s at best (probably less because the older Extreme Pro UHS-I cards wrote at 90-95Mb/s, so Extreme is likely to be closer to 80Mb/s).
A UHS-I Extreme card is not a great match for a Canon R6 unless OP plans to shoot only short bursts or lower quality video.
Cheapchips also offering $55 for the micro card with an adapter. Not sure if it qualifies for the $4.95 postage option there but potentially cheaper if you don't have prime or want another item?
https://www.cheapchips.com.au/memory/sandisk-extreme-pro-256…
Micro SD is generally not recommended for cameras (still - like OP's R6) that take full size SD cards. Obviously a decent choice for drones or action cameras though.
whats the difference between this one? $41.50
https://www.amazon.com.au/SanDisk-Extreme-microSDXC-RescuePR…
Full size vs micro
But one of the pictures shows the sd card adaptor to make it full size?
So this is UHS-I or II? Confused…
Well the link is clearly a UHS-I Extreme (not Pro) v30 card. I think the OP made a mistake and added "Pro" into the title.
UHS-I Extreme PRO cards are a waste of money in camera as they operate at the same speed as slower cards e.g. Samsung EVO (I've tested in a Canon R6 II + many Sony cameras), though it will be faster at offloading pics in a supported card reader.
If you want fast cards go buy UHS-II V60 or V90 cards…
Please note mismatch product and product image on Amazon. Image shows a SanDisk Extreme SDXC card, not a SanDisk Extreme PRO SDXC card. The text description & the SKU is for the Extreme PRO card