RCA splitter

My use is temporary, for comparisons primarily.

For Stereo you need two splitters.

Pair of Jacks on a Device may be too close together for splitter gizmo, while splitter cables preserves tight spacing on the unit (i.e. my Vintage McIntosh Preamp)

Length of splitter cable can move 'joint' up for easy access

This stereo kit is available to buy by the foot

https://www.amazon.com/ROCKRIX-Female-Speaker-Adapter-Splitter/dp/B08PKS42P6/ref=asc_df_B08PKS42P6/?tag=hyprod-20&linkCode=df0&hvadid=475825775681&hvpos=&hvnetw=g&hvrand=18138763782454415975&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003526&hvtargid=pla-1163174276384&th=1

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i.e. I temporarily hook up friend's equipment (or my other stuff) to my system by adding the splitter 'down/back there', then a pair of jacks at accessible height.

Permanent/semi-permanent split, then access less important.

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You might need 'two in' and/or 'two out' depending on what you are doing

Splitters and Y-connectors are fine. I'd defy anyone to tell when one is in use.

Thing I've noticed when trying splitters is it seems to not only split the signal but also split the strength of the output, something I've noticed on many pre-amps which have two outputs. FWIW

Thanks for your responses. I'm going to give these a try https://silversonic.com/products/connectors/y-block-connector/ as they output in two different directions which will facilitate non parallel cable routing which I believe is desirable. 

Balanced splitter, gives you locking connectors, and you choose your lengths for positioning.

https://emotiva.com/products/xbal-1x2?utm_source=google&utm_medium=cpc&utm_campaign=20042245837&utm_content=656394514266&utm_keyword=&gclid=Cj0KCQjwldKmBhCCARIsAP-0rfzAVygLkxXOubiyMyRdSxJH_tWDWfjeHkAq3ELkWv88fJgsd0va648aArnpEALw_wcB

Your chosen splitter, consider supporting the weight of the two cables to minimize downward force on the male end into the units female jack.

you can make your own to use locking connector to hold the weight and avoid possible poor connection

https://www.amazon.com/Parts-Express-Locking-Connector-Solder/dp/B0002KR26I