All the JR servo that we have is JR special made  for Asia market, so the number you may see is difference with the servo from USA or Europe market, it just the difference label only.
Servo's kg.cm S/60° Size (mm) Weight (g) Singapore Dollars: 
Nes-591 or ES-539 5.1 0.24 33.5x19x39 38 S$52.80
ES-579 8.3 0.23 32.5x19x38.5 48 S$79.20
DS-811 4.0 0.21 34.5x19x38 44 S$99.00
DS-8201  4.0 0.19 34.5x19x38 49 S$145.20
DS-8301  6.5 0.19 34.5x19x38 49 S$171.60
DS-8401 11 0.19 34.5x19x39 49 S$171.60
DS-8425 (MG)  11 (15 @6V) 0.18 (0.15 @6V) 34.5x19x38 60 S$184.80
DS-8455 (MG) 6.5 (7.3 @6V) 0.10 (0.08 @6V) 34.5x19x38 60 S$184.80
NES-8700G (MG) 3.5 0.09 34.5X19X38 60 S$211.20
NES-810G 2.4 0.10 34.5x19x39 47 S$132.00
NES-8300 Super servo 6.5 0.19 34.5x19x38 52 Ask
SX8000G for G6000T gyro 3.5 0.09 34.5x19x39 65 Ask
DS8511 15 0.19 35x21x40 66 S$211.20
Receiver . . . . .
R-135 FM  FM 3ch 40mhz . . S$98.00
R-330S Spcm 3ch 40Mhz . . S$148.00
R-700 FM 7ch 35/36/40/72mhz . . S$120.00
Nes-649S  Spcm 9ch 29/35/36/40/72mhz .(Limited stock) . S$198.00
R-900S Spcm 9ch GOLD PIN 29/35/36/40/72 . . S$210.00
R1000DS Spcm 10ch 
Dual conversion
35/36/40/72mhz . . S$308.00
Crystal set  for Tx and RX a set  Single con. R700/649S/ R900 29/35/36/40 mhz . .. S$42.80
Crystal set  for Tx and RX a set  Single con. R700/649S/ R900 72mhz . . S$58.40
Module FM  for X3810, 9X 10X 29/35/36/40/72Mhz . . . S$120.00
Accessories: . . . . .
. Gold switch harnes . . . S$22.40
. TX Stick extension Blue or Red . . . S$22.40
. Tx 8N 1100L 9.6V 1100mAh for 9X use. . . . S$84.00

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