I have seen it in the singular "porta-mopa" > mop holder

http://www.venexport.com/comp/gen/4909.html
PORTA-MOPA MOP HOLDER

http://www.farrarbrothers.co.uk/PDF Catalog/Farrar Brothers ... (See page 17)
ALH8 1500 x 25ø x 1.2 ●●●●●
Plastic Kentucky mop holder / Kentucky-Mopphalter aus Kunststoff
Pince à faubert Kentucky en plastique / Porta-mopa de plástico Kentucky
KEN/CLIP ●●●●
Grey plastic Kentucky mop holder / Kentucky-Mopphalter aus grauem
Kunststoff / Pince à faubert Kentucky gris en plastique
Porta-mopa de plástico gris Kentucky

http://www.euro-system.pl/download/tts/katalogi_produktow/sm...

https://www.google.com.jm/search?q="porta-mopa"&rlz=1C1TSNP_...

HTH!

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Note added at 12 hrs (2013-11-23 12:45:39 GMT)
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Spanruss (I disagree with you)! The mop holders are not the brackets mounted on walls (the holders are the disposable part whether metal or plastic where the mop fits into, i.e. "head" of the mop). And I posted more than one link!

Given that the Asker is also from Venezuela, and assume the text too, here are additional links:

http://listado.mercadolibre.com.ve/EASY-MOP-LA-MOPA-MAGICA_O...

It is not the handle either:
http://articulo.mercadolibre.com.ve/MLV-415933741-porta-mopa...


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Note added at 12 hrs (2013-11-23 12:57:41 GMT)
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Spanruss: this link shows what is referred to as the clip (see photograph on page 17) http://www.farrarbrothers.co.uk/PDF Catalog/Farrar Brothers ...
Plastic Kentucky mop holder
Porta-mopa de plástico Kentucky
KEN/CLIP ●●●●

Grey plastic Kentucky mop holder
Porta-mopa de plástico gris Kentucky

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Note added at 18 hrs (2013-11-23 18:20:29 GMT)
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https://www.prisa.cl/catalog/product_info.php?cPath=7_64&pro...

http://www.soin.cl/aseo-industrial/mopas-y-traperos/porta-mo...
PORTA MOPA JANITOR PLASTICO
home / catalogo de productos / mopas y traperos / porta mopas / porta mopa janitor plastico
PRECIO DE PRODUCTO
$ 3.300 +iva
COTIZAR
CÓDIGO
1205
MARCA
ABCO
STOCK
Disponible
PORTA MOPA JANITOR PLASTICO
PORTA MOPA JANITOR PLASTICO PERTENECE A SOLUCIONES:

http://articulo.mercadolibre.com.ve/MLV-415933741-porta-mopa...

http://www.greatdeal.cl/carros-baldes-porta-mopas-mopas/55-p... (great picture here, and it has nothing to do with the mop handle)!
PORTA MOPA HÚMEDA INDUSTRIAL METÁLICO, MANGO ALUMINIO

Porta Mopa Húmeda Industrial Metálico, Mango Aluminio
Porta Mopa Humeda Industrial METAL GALVANIZADO Porta Mopa Humeda Industrial METAL GALVANIZADO
Imprimir
Ampliar
Porta Mopa Húmeda Industrial

Características:
- Material: Metálico
- Longitud: 1,47 metros
- Permite utilizar Mopa Húmeda Industrial de 16, 24 y 32 Oz.