Sorry, ko888 is wrong on the last statement - backwards. When you plug a 3-pin fan into a 4-pin header AND that header is using the proper PWM Mode for control, that 3-pin fan will always run full speed. A 4-pin fan on a 3-pin header WILL be speed controlled. But, that was not your question.
You want to power and control the speed of several 4-pin fans from an asrock z170a - x1/3.1 motherboard. To do that your mobo's CHA_FAN header(s) MUST operate in PWM Mode, and the manual for that mobo says (according to pin labels on p. 21) they do that. Then you must use a 4-pin HUB and 4-pin fans. Now, that device you linked does not look right. With only the photo to use for info, it has some features of a proper Hub, BUT its output connectors all have only three pins, and there does not appear to be any circuit components to convert from PWM Mode to Voltage Control Mode.
Geekwad has the right idea, and the Silverstone unit of his first link is the right type of device. However, the other link to a "Splitty9" unit appears to be only a SPLITTER and not a Hub. The difference is that a HUB gets all power for its fans from the PSU directly, and hence avoids the limit of how many fans (usually about 4) you can connect to one mobo header.
I get that you can't find that Silverstone unit where you are. So here's what to look for. A HUB may be just a connection of wire arms with connectors, or a box with ports on it, or even a circuit board with ports. But here are the important parts that distinguish a HUB.
1. It has ONE input arm with a female (with 4 holes) connector that connects to a mobo 4-pin CHA_FAN header. This picks up the PWM signal from the header and sends back to it the speed signal of only ONE of its fans. Beware of anything claiming to be a Hub or Splitter that does NOT have any connection to a mobo CHA_FAN header; such items are only able to send full power from the PSU to the fans, with NO speed control.
2. It has several output connectors or ports, all male (with pins) that you plug your fans into. Only one of these may have 4 pins, and the others may have only three - Pin #3 in the pattern is missing.
3. It has ONE cable or connector that must be connected to a power output from the PSU - this may be either a 4-pin Molex output, or a SATA power output. This is where all the power for the fans comes from. THIS arm that connects to the PSU directly is what distinguishes a HUB from a Splitter.
Here are examples of each type so you can see what to look for. All of these are HUBs.
All-cable type with 4 output arms
http://www.newegg.com/Product/Product.aspx?Item=N82E16812423164&cm_re=4-pin_splitter-_-12-423-164-_-Product
Silverstone 8-output box
http://www.newegg.com/Product/Product.aspx?Item=9SIAABJ4SF8917&cm_re=4-pin_fan_hub-_-11-999-309-_-Product
Swiftech 8-output box
https://www.amazon.com/Swiftech-8W-PWM-SPL-ST-Way-PWM-Splitter-Sata/dp/B00IF6R4C8/ref=sr_1_2?s=pc&ie=UTF8&qid=1481322342&sr=1-2&keywords=fan+hub
SMAKN circuit-board style
https://www.amazon.com/SMAKN%C2%AE-temperature-controlled-supports-Ports-D-port/dp/B015BZ22G8/ref=sr_1_19?s=pc&ie=UTF8&qid=1481322342&sr=1-19&keywords=fan+hub
This has a male 4-pin Molex connector on it that the PSU's female Molex output connector plugs into, one cable that plugs into your mobo's CHA_FAN header, and 10 output ports. Of those 10, one (labeled "CPU", but ignore that) will send the fan speed signal to the mobo header.
I hope that, with that description, you will be able to find a Hub for your needs.