XT connectors are popular for use in radio control hobbies and other devices needing a reliable power connection and ease of solderability or welding. Each connector is sold as 1 mating set.
Aside from physical size difference, the connectors have different amperage ratings:
XT30: 30A Peak, 15A Continuous (18 AWG Wire)
XT60: 60A Peak, 30A Continuous (12 AWG Wire)
XT90: 90A Peak, 40A Continuous (10 AWG Wire)
Deans (T-Plug) connectors are also popular for power applications requiring up to 30A Peak, 15A continuous (16-18 AWG Wire):
Summary
kyosho
team associated
team losi
traxxas
horizon hobby
horizon hobbies
tamiya
redcat
red cat
redcat racing
arrma rc
hb racing
hpi racing
axial
spektrum
castle creations
reedy
cen
hobbywing
hobby wing
Esptiger esports
Furitek
Holmes hobbies
Protek rc
Tekin
Yeah racing
1up racing
175rc
Bachmann
Dynamite
e-flite
e flite
eflite
fantom
great planes
hot racing
jconcepts
lrp
maclan
ruddog
team brood
xnova
yokomo
usa-1
usa 1
x-maxx
xmaxx
x maxx
traxxas x max
kraton
arma kraton
scx 6
scx 10
scx 24
scx6
scx10
scx24
mad force
inferno
losi eight
8ight
promoto mx
promoto-mx
granite
vendetta
senton
infraction
felony
slash
sledge
xrt
slash
stampede
slayer
udr
unlimited
trx
trx4
trx-4
lipo
lithium polymer
desert
desert truck
desert buggy
super baja rey
blizzard
rival
short course
stadium truck
remote control
1738-1438
1738-1437
1738-1436
1738-1438-ND
1738-1437-ND
1738-1436-ND
1568-1659-ND
1568-1659-ND
FIT0586
FIT0588
FIT0587
t plug
mini t plug
t connector
xt 30
xt 60
xt 90