Can someone advise on a good brand or specific item with regards to a wireless Shutter release? Thank you
It depends on what camera you have (not all support a wired shutter release), whether you want additional features, etc.
If you have an Android or Apple smartphone that has wifi support, most of the new camera models support the ability to be controlled from the manufacturer's smartapp (OIShare in the case of Olympus/OM, and ImageApp from Panasonic). You would set up the camera and phone to be connected, and use the app to take pictures remotely. In this case, you don't have to buy anything. I do find the app to not be as easy as using a wired or wireless shutter release, particularly if I am doing fireworks, where using a screen can ruin your night vision, and it isn't as easy to use in the dark as just pressing a button.
Basically, neither Olympus nor Panasonic support a wireless shutter release on micro 4/3rds cameras other than the wifi support from Android and Apple cell phones. Instead, they provide wired shutter releases. If you want a wireless shutter release, then you would get a third party wireless shutter release that uses the same plug as the wired shutter release. And note, a lot of times, the lower end models don't support a wired shutter release. In the Olympus line-up, the E-M10 mark III/IV don't support a wired shutter release. I haven't kept track of the non-OMD Pens, so I don't remember whether they support a wired shutter release.
Olympus micro 4/3rds cameras that support wired shutter releases use 2 different releases. The wired RM-UC1 release uses the old 12-bit cable that Olympus used to use for USB, analog video out, and shutter release. The wired RM-CB2 release is used by the E-m1 mark II/III, E-m1x, and E-m5 mark III cameras. It uses a 2.5mm audio plug for the shutter release. This release uses the same pinout that some/many Canon cameras use, which means it can be easier finding a third party shutter release.
There is a third release (RM-CB1) that was used on several of the older DSLRs (E-1. E-3, E-5, and maybe the E-30) that is not used by any of the micro 4/3rds cameras. There also were two older infrared releases (RM-1 and RM-2) that are not used on any micro 4/3rds cameras.